A candle placed 25 cm from a lens, forms an image on a screen placed 75 cm on the other end of the lens. The focal length and type of the lens should be
|
(a) + 18.75 cm and convex lens |
(b) – 18.75 cm and concave lens |
|
(c) + 20.25 cm and convex lens |
(d) – 20.25 cm and concave lens |
(a) + 18.75 cm and convex lens
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The mass equivalent of 931 MeV energy is
|
(a) 1.66 |
(b) 6.02 |
(c) 1.66 |
(d) 6.02 |
When the current through a solenoid increases at a constant rate, the induced current
|
(a) Is constant and is in the direction of the inducing current |
|
(b) Is a constant and is opposite to the direction of the inducing current |
|
(c) Increases with time and is in the direction of the inducing current |
|
(d) Increases with time and opposite to the direction of the inducing current |
The effective resistance between points P and Q of the electrical circuit shown in the figure is
|
(a) 2Rr/(R + r) |
(b) 8R(R + r)/(3R + r) |
(c) 2r + 4R |
(d) 5R/2 + 2r |
Calculate the amount of charge flowing in 2 minutes in a wire of resistance 10 W when a potential difference of 20 V is applied between its ends
|
(a) 120 C |
(b) 240 C |
(c) 20 C |
(d) 4 C |
In Millikan oil drop experiment, a charged drop of mass 1.8 
is stationary between its plates. The distance between its plates is 0.90 cm and potential difference is 2.0 kilo volts. The number of electrons on the drop is
|
(a) 500 |
(b) 50 |
(c) 5 |
(d) 0 |
Size of nucleus is of the order of
|
(a) |
(b) |
(c) |
(d) |
The curve between charge density and distance near P-N junction will be
(a)
|
(b)
|
(c)
|
(d)
|
