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What is the nature of light? "luminous” (a) Distinguish between and "illuminated” objects. (b) How may objects be rendered luminous? (a) What evidence have we to prove a that vacuum? through travel can light (b) Distinguish between opaque, and sub- transparent translucent stances. Give examples of each. (a) What Is me... |
and the normal). In each case these two angles will be found to be equal, and the incident ray, the reflected ray and the normal will all be found to be in the plane of the disc. Hence we can state the two laws of reflection as follows: First Law: The angle of reflection althe angle of ways equals incidence or Z r = Z... |
a surface, the directions. individual rays are scattered or diffused due to their being reflected in different directions. To avoid glare it is often necessary to promote diffusion of light. Unglazed paper is used for newspapers, and for Smooth Surface Rough Surface Regular Reflection Irregular Reflection (a) (b) Fig.... |
. IV: 12 TO LOCATE IMAGES IN PLANE MIRRORS These phenomena observed experimentally can be shown to be true as a geometrical consequence of the laws of reflection, Sec. IV; 9. Let us consider the simplest possible case, that of a point object, O, the image of which, I, is viewed by an eye BD (Fig. 17:5). O is sending ou... |
also a series of images representing the side of O facing mirror These multiple images '^^2 are due to the image formed in one mirror, acting as the object, which in turn forms an image in the second mirror, and so is absorbed at each reflection, each succeeding image is fainter than the one preceding. Since some ligh... |
rors. Fig. 17:10 (a) Concave or Converging. (b) Convex or Diverging. A few terms used in connection with curved mirrors need to be defined (Fig. 17:11): 188 REFLECTION OF LIGHT—MIRRORS Sec. IV: 14 Fig. 17:12 Action of Curved Mirrors. (A) Concave. (B) Convex. Centre of Curvature, C, is the centre of the imaginary sphere... |
Similarly, if we insert a convex mirror in place of the concave one, and repeat the above, it will be found that the reflected rays diverge as though coming from a point behind the mirror. This virtual point locates the principal focus of the convex mirror. 189 Chap. 17 LIGHT IV: 15 IMAGES IN A CONCAVE MIRROR In chapt... |
Fig. 17:14 Concave Mirror of an Object Placed Beyond F. For example, if the focal length of the concave mirror was 20 cm., the object 60 cm. from the mirror, and 12 cm. high, our construction would be as above (Fig. 17:14), using the scale 10 cm. = 1 cm. REFLECTION OF LIGHT—MIRRORS Sec. IV; 17 Draw principal axis, PV.... |
behind virtual, smaller than the the mirror, object, and erect. The same method is used as with the concave mirror to verify this geometrically (Fig. 17:16). IV: 17 HOW THE EYE SEES THE IMAGE discussed As previously section IV: 12, the eye sees the image by means of rays which actually come from the object, but which ... |
_ 1 — + Do Dr 7 — + 1 1 1 T 1 15 15 1 _ 1 D,“ 5 :.2Di — 15 :.Di =7.5 The image is located 7.5 in. from the mirror. 192 Ho— 2 in. Do = 15 in. Dj — 7.5 in. REFLECTION OF LIGHT—MIRRORS. Hi ^ A ‘ Ho~ Do. Hi _ 7.5 ~ 15'2?. ‘ Sec. IV: 19 The image is 1 in. tall. Check these results by making an accurate scale construction t... |
reflected through points some distance from the Conversely, if a focus source of light is placed at the principal focus, the reflected rays will not form a parallel beam, but the outer ones will be scattered and hence the light is weakened. Fig. 17:19 Spherical Aberration in Curved Mirrors. To overcome this parabolic ... |
? What kind of image is seen? 8. An object is located just beyond the centre of curvature of a concave mirror. (a) By means of a diagram locate its image. (b) Show how the eye sees the image. (c) State the characteristics of the image. 9. (a) State uses of plane, concave and convex mirrors. (b) How does a searchlight p... |
the focal length of the mirror. 12. An object is 15 cm. from a convex mirror of focal length 20 cm. Calculate the image distance. 4. An object 15 cm. high is located (i) 75 cm. (ii) 60 cm. (iii) 45 cm. (iv) 30 cm. (v) 20 cm. from a concave mirror whose focal length is 30 cm. 13. The focal length of a concave mirror is... |
into water, or from water into air, can be illustrated Fill a tank with water containing a small amount of fluorescein, or a little sodium thiosul- easily. 196 REFRACTION OF LIGHT-LENSES Sec. IV: 23 from air into glass, or from glass into Place a semicircular block of glass air. on the optical disc, so that its flat e... |
toward the normal as it enters the denser medium. Conversely, the wave-front would swerve away from the normal as it speeds up on passing into an optically less dense medium. No bending occurs if the light enters the new medium at right angles to the surface, for the entire wave-front would be slowed down or speeded u... |
index of refraction is said to have a REFRACTION OF LIGHT-LENSES Sec. IV: 25 high optical density, because it permits light to travel through it at a relatively Such substances refract slow velocity. light to a greater extent than do those with a smaller index of refraction. The brilliance of diamonds, and other preci... |
THROUGH PRISMS A prism consists of a wedge-shaped portion of a refracting substance, bounded by two plane surfaces inclined at an angle to each other, this angle being called the refracting angle. When a ray of light enters such a prism it is slowed down, and therefore refracted toward the normal. On leaving, it speed... |
, that is, the angle of refraction equals 90°. This angle of incidence is angle. When the called the critical incident angle exceeds the critical angle the light is completely reflected, a phenomenon known as total reflection (Fig. 18:8). Using the semicircular block of glass on the optical disc as in section IV:21, sh... |
brilliancy of diamonds, brilliants, and cut-glass dishes is due to total reflection. The greater the index of refraction of a substance the smaller is its critical angle. Diamonds have a large index of refraction (Sec. IV: 23) and consequently have a small critical angle. The surfaces of the diamonds meet each other a... |
LENSES A lens is a piece of transparent refracting medium, usually glass, bounded by two spherical surfaces, or by a plane and a spherical surface. There are two main types: (a) Converging or Convex Lenses are thicker at the centre than at the outer edge. Such lenses always refract rays of light so as to converge them... |
focus is a virtual point, and is that point on the principal axis from which a beam of light, which is parallel to the prindiverge on cipal being refracted through the lens.) axis, appears to Focal Plane is a surface that passes through the principal focus perpendicular to the principal axis of the lens. Focal Length ... |
x lens with a real principal focus has a positive focal length and a 4- power; a concave lens with a virtual principal focus has a negative focal length and a — power. If a lens is used in a different medium, its focal length and therefore its power will change. This can be shown by placing a lens in a tank of turbid w... |
on which the sun burns a record. lens. This ray may be considered straight through the as lens (Sec. IV; 28). passing recorder. Real care must be observed in setting up There must be no obthe structions that would shield the recorder It must be placed from the sun’s rays. table, and made perfectly on a rigid Instructi... |
21 it will be observed that concave lenses can form virtual images only. These are 207 Chap. 18 LIGHT always erect, smaller than the object, and located at less than the focal dis(Fig. 18:21). A tance from the lens close similarity will be noted between the images formed by concave lenses and those formed by convex mi... |
your answer by making an accurate scale diagram. / = — 4 in. Do = ( — since / is virtual) 12 in...Ill D~ f.•. 1 + '- = -1 12 Di 4. 1 _ 1 1 _ —3 —1.\Di = -3 Image distance is 3 in. Note: Since the image distance is negative, therefore, the image is virtual. Hi =? Ho = I in. Di = 3 in. Do= 12 in...Hi _1^ ‘ Ho~ Do ‘ ^- 1... |
(d) The velocity of light in a diamond is 75,300 miles per second. What is its index of refraction? (a) How do you account for shimmering effect seen in the above a hot radiator? (b) How does the same principle account the twinkling the the for of air stars? 4. Place a thick glass plate on a line drawn on a piece of p... |
) State the characteristics of the image. constant for all colours of light? 13. (a) What do we mean by the magni- Explain your answer. fication produced by a lens? 211 Chap. 18 LIGHT 9. (b) How does the magnification depend on image distance and object distance? B 1. What is the index of refraction of a liquid in whic... |
image of an object 24 ft. from a lens is focused clearly on a screen 3 ft. from the lens. What is the focal length of the lens? 12. A convex lens forms a virtual image at a point 1 2 cm. from the lens. The object distance is 8 cm. Find the focal length of the lens. 13. A tree 1 00 ft. from a camera lens has its image ... |
men have known that colourless glass of certain shapes, as well as frost, diamonds and other crystals, produce light of many colours when illuminated by white light. Sir Isaac Newton Until the time of everyone supposed that or crystals produced the light by giving something to the light as it was reflected by, or tran... |
, it follows that they must be velocities through the prism. Red light, bent the least, must slow down the least on entering the prism and therefore speeds up the least on leaving. In contrast, violet light must slow down the most on entering, and speed up the most on leaving the prism. travelling different at A questi... |
Chap. 21, Exp. 16). He first arranged two prisms with their refracting edges in opposite directions. On passing white light through these reversed prisms, white light was obtained through Fig. 19:2a shows that the first them. prism disperses the colours, while the second prism recombines them by reversing the original ... |
° from drops of water higher 216 (Fig. in the sky, and the violet rays come at an angle of 40° from drops of water lower 19:3b). The other in the sky colours come from drops between these angles. The rainbow has the shape of a bow, since the eye of the observer is at the apex of a cone from which he sees the coloured r... |
active substances). radiations are propagated as waves with the same velocity as light, the difference in their properties being due to their different wave-lengths. The relationship between these various electromagnetic is shown waves, diagrammatically in Fig. 19:4. as they are called, IV: 39 SPECTRUM ANALYSIS The sp... |
the Bunsen flame only in the case of subvaporized. stances Other substances must be vaporized, using an electric arc or a spark dis- which easily are Fig. 19:7 An Electrical Discharge Tube. The spectra of incandescent charge. gases are usually obtained by means of special tubes containing a sample of the gas at low pr... |
. Psychology considers colour through the physical operation of the eye and the mental impression created by colour on the brain. As a result, the actual perception of colour is a highly personal experience which may be influenced by such factors as health, fatigue and response of the eye to colour (colourAccording to ... |
circle are complementary. White is the total addition of colour, is of then, the result spectrum, and reflects and not, as often believed, the absence of colour. It is produced when a surface reflects all colours equally. Black, on the other hand, is perceived when a surface absorbs all colours and reflects none. Colo... |
this reason an article of clothing may appear quite different in the sunlight than when seen under artificial light. (c) Coloured Lights— The Additive Theory Having produced different coloured lights by the use of filters, two or more of these may be added together to produce still other colours. The three colours, re... |
with its use in traffic control. (d) Colour Vision are there theory, widely The way in which light is changed into the sensation of sight is not definitely The most known. accepted the Young-Helmholtz theory, of colour three states nerves in the normal eye. One of these sets of nerves responds only to blue light, anot... |
: spectrum, dispersion. (b) Why does a prism deviate violet light more than red light? (c) Calculate the vibration frequency of violet light (See table, p. 214, for wave-length of violet light). 2. Describe and explain three methods for recombining the spectral colours into white light. 3. Explain how refraction produc... |
APTER 20 OPTICAL INSTRUMENTS 1553, Porta, Baptista and camera. Johann Kepler, 1604, later added a lens and then a combination of lenses. From these simple beginnings have come many types of cameras ranging from the relatively inexpensive family-type cameras, through the more expensive press and movie cameras, up into t... |
contains materials which are sensitive to light. The plate is coated with an emulsion consisting of gelatine and a silver salt. Light decomposes this silver salt so that when “developed” and “fixed” a negative is obtained consisting of a dark deposit of silver in places corresponding to the light parts of the original... |
parts of the eye. is also largely nutritive in function. The aqueous and vitreous humours are jellylike materials filling the spaces within It the eyeball, which help to keep its spherical shape. Behind the cornea is a coloured diaphragm called the iris. This is really an Fig. 20:3 The Structure of the Eye. 228 extens... |
focused by the unaided eye. their characteristic The retina is the innermost layer of the eye and is sensitive to light. The retina is composed of visual cells, nerve cells, and the fibres which connect these and conduct the nerve impulses to the brain. The visual cells are of two types, called rods and cones, so name... |
a focus on the retina. but is tary, 2. Far-sightedness A far-sighted person cannot see clearly objects close to the eye although distant objects may be distinctly The defect is due to the axis of the eyeball being too short or the crystalline lens not sufficiently converging so that rays from a nearby object tend to c... |
hardening of the crystalline lens, or of the ciliary muscles. is evidenced by both near and far objects being indistinct. Clear vision by the unaided eye is possible over only a very restricted range. Two pairs of spectacles are required by such people, one pair (convex) for reading, and another pair (concave) for dis... |
ESCOPE (a) Refracting Telescope The method by which the telescope works is similar to that of the microscope. The refracting telescope consists be the focal larger length of an arrangement of two convex lenses for viewing very distant objects (Chap. 21, Exp. 19), The objective should have a very great focal length, for... |
to cast a magnified image of a slide or transparency upon a screen coloured some distance away. Fig. 20:12 shows the essential structure of such a projector. A study of the paths of the light rays shown in the diagram will serve as an excellent review of some of the work covered earlier in concave mirrors and convergi... |
c) the terrestrial telescope, as to: 9. (i) essential parts. (ii) how each works. (iii) types of images obtained. In a slide projector: (a) Where is the light source relative to (i) the concave reflector, (ii) the condensing lens? Why is it placed in this position? (b) Where is the slide relative to the principal focus... |
of the camera held stationary so that the ground-glass screen is a fixed distance from the pin-hole, observe the size and other characteristics of the image of the candle placed at some distance from the camera. Move the camera closer to the candle and note the size of the image. 2. Holding the camera a fixed distance... |
PQ and RS. Produce these lines until they meet at T. Through T draw TN perpendicular to AB. With a protractor measure angles PTN and STN. 5. Repeat, with other positions of the pins. Observations 1. Observation No. Angle of Incidence Z PTN Angle of Reflection Z STN 1. 2. 3. 238 EXPERIMENTS ON LIGHT 2. When the inciden... |
what you see. Observations 1. Observation Number Distance of Object OM Distance of Image IM Size of Angles AT M 1. 2. 3. 2. How does the size of an object and its image compare? 3. Which hand appeared to be raised in the mirror? What term applied to the image describes this phenomenon? 4. What kind of image is it? Con... |
the image is clear and sharply defined. 2. Measure the distance of the image from the vertex of the mirror. Observations 1. What is observed when parallel incident rays are reflected from the mirror? 2. Describe the image obtained when the object is at infinity. 3. What is the distance of the image from the vertex of ... |
1. What kind of image is produced by a convex mirror? 2. Describe the position and characteristics of the images produced by a convex mirror for all positions of the object. Questions 1. How would you find the focal length of a convex mirror? 2. Why may such a mirror be called a diverging mirror? 3. Construct a geomet... |
through a glass plate with parallel sides. (Ref. Sec. IV: 24) 244 EXPERIMENTS ON LIGHT Apparatus Same apparatus as in experiment 8. Method 1. Lay the sheet of paper on the tack board. Place the glass block on the sheet of paper. Outline its position carefully. 2. Stick two pins A and B upright in the paper, about 2 in... |
no parallax between it and the image of the object pin. 3. Determine the distance of the object pin, and of the search pin from the surface of the water, thus finding the real and apparent depths. 4. Repeat the experiment using different depths of water. 5. Tabulate your observations and determine the average value fo... |
and SR to meet at D. Measure the size of Z D (angle of deviation). 6. Construct the normals at Q and R. Measure the angle of incidence and the angle of emergence. 7. Repeat on separate diagrams for three other angles of incidence, including the special case where the angle of incidence is equal to the angle of emergen... |
the optical centre of the lens? Conclusions 1. What effect do (a) a convex lens, (b) a concave lens, have on light rays incident upon them? 2. Define: principal focus, focal length. Questions 1. What other name may be given to (a) a convex lens, (b) a concave lens? Why? 2. Why did we use an infinitely distant object i... |
would you find the focal length of a concave lens? 2. Why may such a lens be called a diverging lens? 3. Construct a geometric diagram to locate the image of an object produced by a concave lens, EXPERIMENT 15 To study the dispersion of white light into the spectrum. (Ref. Sec. IV:36(a) Apparatus Projection lantern, s... |
in experiment 15, place the second converging- lens in the spectrum. Move the lens until the image is brought to a focus on the screen. Again note what is observed. 3. Examine Newton’s colour disc. Strongly illuminate it with white light from the projection lantern. Rapidly rotate it. Note the effect obtained. Place o... |
and blue filters in the path of the light beam. Note the colour of the light obtained. 4. Repeat 2 using all three filters (red, yellow and blue) in the path of the beam. Note what is obtained. Observations Describe carefully all that is observed. Represent your observations by means of simple diagrams. Explanation Ac... |
however, to be too much in advance of its time and was soon forgotten. For the next hundred and fifty years there was little progress, but in the latter part of the eighteenth century magnetism began to be recognized as the exact science that it has become today. 22:1). V : 2 SOME PROPERTIES OF MAGNETS When an iron ba... |
V:3 THE EARTH AS A MAGNET In the previous section it was shown that a suspended magnet always comes to rest along a north-south line. The magnet behaves in this way because the earth itself possesses a magnetic field as if it contained a huge bar magnet lying (Fig. 22:4). nearly parallel to its axis Why is the end of ... |
-pole in our definition we obtain the conventional direction for the lines of force, i.e., from the N-pole of the magnet, which would repel the free N-pole, to the S-pole of the magnet which would attract it. The effect of a magnet is noticeable over a considerable space surrounding it. This can be demonstrated by plac... |
component of this field that activates the magnetic compass. The exact direction of the magnetic lines of force may be determined by the use of a dipping needle. This consists Fig. 22:8 Dipping Needle. thus be 90°. stand vertically and the reading on its At the protractor will magnetic equator the needle will be horiz... |
the molecules become aligned as shown in Fig. 22: 10b. At the end of the bar last touched by the N-pole of the magnet there will be many S-poles of the molecular magnets and thus it will act as the S-pole of our new magnet. The opposite end, having many molecular N-poles will be the new N-pole. In the central region o... |
of the earth. (c) Why doesn’t a compass-needle point to the true north pole? Define angle of declination. (a) Define line of magnetic force. (b) Draw the magnetic field about a bar magnet. (c) State three fundamental characteristics of these lines of force. (a) Define angle of inclination or dip. (b) What would be the... |
all poles. 5. How would you use a compassneedle to distinguish between three bars similar in shape and appearance if one is brass, the second is unmagnetized iron and the third is a magnet? 6. You are given two iron bars — one magnetized, the other not — and nothing else. Describe carefully how you could determine whi... |
of such men as Gilbert and Gray in England, du Fay in France, and Franklin in America that many of our fundamental concepts of electricity have arisen. The study of electrostatics has paved the way for advancement in current electricity. remained isolated fact V: 10 ELECTRIC CHARGES As mentioned above, the phenomenon ... |
are protons within the nucleus. 269 Chap. 23 MAGNETISM AND ELECTRICITY Hydrogen Oxygen Neon Magnesium Chlorine Fig. 23:2 Diagrams of Several Atoms— Electrons (•), Protons ( + ), Neutrons (n). 5. There are over one hundred different kinds of atoms known at the Scientists believe that present time. even more will be ide... |
When the charged pith balls are now approached by an object bearing the same kind of charge, they will be repelled from it. If the charge on the object is opposite to that placed on the pith balls, they will be attracted to it (Chap. 31, Exp. 14). ball to the rod which, being positively charged, has a deficiency of el... |
of the electroscope. The similar charge on the plate and leaf leaf diverges. The extent of this divergence is an indication of the strength of the charge. If the knob is now approached by an object bearing the same kind of charge as that on the electroscope, there will be further divergence of the goldIf, however, the... |
rod is now removed and on B) the spheres allowed to touch, it will be found that no charge remains on either sphere. We may conclude then, that induced charges are equal. still Exp. 18). The leaf diverges as shown in Fig. 23:7 because electrons are repelled to the plate and leaf. Keeping the charged rod near, touch th... |
is little danger from the discharge because of the small quan- tity of electricity involved. Canadian Laboratory Supplies Ltd. 275 Chap. 23 MAGNETISM AND ELECTRICITY 1. In conductor (a) the leaves of the electroscope show the same divergence matter what part no is touched by the proof plane. 2. In conductor (b) the di... |
an “electric wind”. Franklin made use of this action of points as he designed the lightning-rod to protect buildings against the dangers of lightning. As a charged cloud passes its ning with occurs over the earth it induces the opposite charge on objects below. If the charge becomes great enough a flash of lightaccomp... |
(d) lightning-rods are sharply pointed. (e) lightning-rods are connected by a good conductor to ground. A positively charged cloud hovers over a tall church spire. What will be the resulting electrical condition of the spire? What will happen if a large enough charge accumulates on the cloud? 6. 7. (b) Explain how to ... |
storage battery used to start a car; these are just two modern forms of the voltaic cell. A voltaic cell consists of two dissimilar materials immersed in a solution of an acid, called the base, or salt, electrolyte. voltaic The simplest form of cell consists of a copper plate and a zinc plate placed in a vessel contai... |
and shapes have been made to fill many needs. They are widely used for flashlights, portable radios, telephones, hearand many other ing devices used by the armed forces and industry. lanterns, aids, V:26 THE ELECTRIC CIRCUIT The flow of electrons in a wire is so similar to the flow of water in a pipe a comparison may ... |
-unit is the coulomb (/) — unit is the ampere {V ) — unit is the volt (R) — unit is the ohm Potential difference (d) Resistance (c) Smaller or larger units are obtained by using submultiples or multiples of these as: 1 milliampere = 1/1000 ampere 1 microampere = 1/1, 000, 000 ampere 1 millivolt = 1/1000 volt 1 megohm V... |
). All In the parallel or shunt type of connection the conductor from the positive terminal of the source is connected to one terminal of each appliance and the negative terminal of the source is connected to the other terminal of each Electron Flow 4- Battery Appliance = © (I) (£) (p Fig. 24:4 Parallel Circuit. applia... |
Fig. 24:7a. Wall switches are smaller variations of the same type. (b) Push Button Switch This familiar type is shown in Fig. 24:7b. It is used to control low-voltage Fig. 24:7 Switches (a) Main House Switch (b) Push Button Switch circuits in which the current is required for short intervals only. Electric doorbells, ... |
, a lamp, a switch. 1. 2. 3. (a) What is an electric current? (b) How is an electric current produced? (a) Make a diagram of a simple voltaic cell. Mark the direction of the electric current (electron flow). (b) What determines the voltage of such a cell? (c) What transformation of energy takes place in a voltaic cell?... |
25 MAGNETISM AND ELECTRICITY this law is true only if the temperature remains constant (Sec. V:34). The value of the constant derived above is known as its resistance {R) The unit of resistance is the ohm which may be defined on the basis of Ohm’s Law as being the resistance of a conductor which permits a current of o... |
NETISM AND ELECTRICITY circuit (b) the current in the circuit (c) the voltage drop across each lamp. fi = 30 ohms t2 = 20 ohms (a) (b) ri = 2)0 ohms 72 = 20 ohms R =? v = no volts /? nr 50 ohms 1 =? / = 2.2 amp. 7i = 30 ohms rg rr 20 ohms 1*^ V =110 volts H'R = Ti + 72 (series connection) i? = 30 + 20 = 50 total resist... |
many megohms as found in radio receivers. In general, however, resistors may be classified or variable. either fixed as (a) Fixed Resistors These may be constructed of short lengths of metal strip for very low resistances. Carbon or wire coils will provide higher resistances. Carbon resistors are frequently used in ra... |
:5 Rheostat. of wire wound on a porcelain tube. Above the coil is supported a metal bar along which moves a metal spring which can make contact at any turn of the coil. Connections are made to the end of the bar and to the end of the coil to enable the resistance in the circuit to be readily adjustable by moving the sp... |
Describe a resistance box and a rheostat. State the purposes of each, (b) What is the effect of removing a plug from a resistance box? (a) Describe two methods for finding the resistance of a conductor. (b) In an electrical circuit, the ammeter reading is 5.5 amperes and the is 77 volts. potential What is the resistan... |
6 ohm the total (a) Calculate resistance between A and B when the switch is closed. (b) Find the current in the 6 ohm resistance with switch open. (c) Find the current in the 1 2 ohm resistance with switch closed. 10. A cell with a potential difference of 2 volts and negligible resistance sends a current through two r... |
the decomposition of water by electricity, or as we speak of it now, the electrolysis of water. Davy showed that the in volume of hydrogen produced is double His most striking disthat of oxygen. coveries were the breaking apart by electricity of the alkalis, caustic soda and caustic potash. Arrhenius explained these p... |
ociated into positive hydrogen ions (H"^) and negative sulphate ions (S04““). H2S04^2H^ + SO4-- The water is slightly dissociated into positive hydrogen ions and negative hydroxyl ions (OH“) : H 2O + OH-. Fig. 26:1 Electrolytic Cell as Used in the Electrolysis of Water. supply. Thus we have electrons moving from the ne... |
cathode, copper will be deposited at the cathode soon after the voltage is applied (Chap. 31, Exp. 26). the copper sulphate is highly dissociated into positive copper ions (Cu^^) and negative sulphate ions (SO4--). In solution Cu SO 4 Cu"" + SO 4 - - The water is slightly dissociated into positive hydrogen ions (H"^) ... |
., the amount of any sub- 298 stance deposited) by an electric current is proportional to the quantity of electricity passed (Quantity = Current X Time.) 2. The amounts of different substances deposited by the same quantity of electricity are proportional to their equiva(The equivalent weight lent weights. of a substan... |
chemical equivalent of copper = 0.000329 In 1200 sec. weight of copper deposited =0.19 gm..'. In 1 sec. weight of copper deposited = 0.19 = 0.000158 srm. Current flowing when 0.000329 gm. copper is deposited in 1 sec. = 1 amp. Current flowing when 1 gm. copper is deposited in 1 sec. = amp. 000329 1200 Current flowing w... |
it is stripped off, backed with a metal of low melting-point to strengthen it and is then ready for use. This reproduction can be used over and over again and is readily stored for later editions. V:46 THE LEAD-ACID STORAGE BATTERY When the simple voltaic cell (Sec. V;23), and the dry cell (Sec. V:25), become discharg... |
the formation of water causes dilution of the acid in the cell. Thus, discharged cells are indicated by a lowering of the P.D. of the cell and a decrease in the specific gravity of the electrolyte. A fully charged cell should have a P.D. of approximately 2.2 volts, and 301 Chap. 26 MAGNETISM AND ELECTRICITY a specific... |
for emergency lighting-systems. V : 47 Q U E S noNS A 1. (a) Define: ion, electrolyte, non-elec- trolyte, electrolytic cell, anode, cath- ode, anion, cation, electrolysis. (b) Outline Arrhenius’ theory of ion- ization. 2. Explain how the electrolyte completes In the electrolysis of water describe: (a) the condition of... |
obstorage served caring for a in battery? B Calculate the strength of the current. 6. An ammeter connected in series with a silver voltameter reads 1.50 amperes. In 50 minutes the increase in weight of the cathode is 4.947 gm. What Is the error in the ammeter reading? 7. A copper voltameter and a water voltameter are ... |
concentric circles with the wire as centre. Thus the pattern of the lines of magnetic force becomes apparent. The direction of these lines of force may be determined Left Hand Rule to DeterFig. 27:2 mine the Direction of the Magnetic Field about a Conductor. by placing a number of small magnetic compasses on the cardb... |
a wire (Fig. 27:4) is referred to as a helix or solenoid. If a conductor is formed into a single loop, the lines of Fig. 27:4 A Helix or Solenoid. magnetic force which surround the wire will pass through the centre of the loop as shown. Note that the magnetic field inside the loop will be more dense than outside since... |
. Such an arrangement is known as an electromagnet. Soft iron makes the most satisfactory core, since a temporary magnet is produced. When the current in the is stopped the magnetism of the coil core is lost in a short time. An increase in the number of turns in the coil or an increase in the strength of the electric c... |
. The automobile generator cut-out relay is a magnetic switch which opens and closes the circuit between the genbattery erator (Sec. V:63) and the 307 Chap. 27 MAGNETISM AND ELECTRICITY An Electromagnet Used for Lifting Scrap Iron. steel Co. of Canada Ltd. (Sec. V:46). It serves to connect the generator to the battery ... |
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