Cathode rays are similar to visible light rays in that
|
(a) They both can be deflected by electric and magnetic fields |
|
(b) They both have a definite magnitude of wavelength |
|
(b) They both have a definite magnitude of wavelength |
|
(d) They both can expose a photographic plate |
(d) They both can expose a photographic plate
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Two thin wire rings each having a radius R are placed at a distance d apart with their axes coinciding. The charges on the two rings are +q and -q. The potential difference between the centres of the two rings is
|
(a) Zero |
(b) |
|
(c) |
(d) |
The heat developed in an electric wire of resistance R by a current I for a time t is
|
(a) |
(b) |
(c) |
(d) |
An inductor, L a resistance R and two identical bulbs, 
and 
are connected to a battery through a switch S as shown in the figure. The resistance R is the same as that of the coil that makes L. Which of the following statements gives the correct description of the happenings when the switch S is closed
|
(a) The bulb B2 lights up earlier than B1 and finally both the bulbs shine equally bright |
|
(b) B1 light up earlier and finally both the bulbs acquire equal brightness |
|
(c) B2 lights up earlier and finally B1 shines brighter than B2 |
|
(d) B1 and B2 light up together with equal brightness all the time |
A parallel plate capacitor has an electric field of 
between the plates. If the charge on the capacitor plate is 1μC, the force on each capacitor plate is
|
(a) 0.5 N |
(b) 0.05 N |
(c) 0.005 N |
(d) None of these |
An eye specialist prescribes spectacles having a combination of convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. The power of this lens combination in diopters is
|
(a) + 1.5 |
(b) – 1.5 |
(c) + 6.67 |
(d) – 6.67 |
