A plane electromagnetic wave is incident on a material surface. If the wave delivers momentum p and energy E, then
| (a) p = 0, E = 0 | (b) p ¹ 0, E ¹ 0 | (c) p ¹ 0, E = 0 | (d) p = 0, E ¹ 0 |
A plane electromagnetic wave is incident on a material surface. If the wave delivers momentum p and energy E, then
| (a) p = 0, E = 0 | (b) p ¹ 0, E ¹ 0 | (c) p ¹ 0, E = 0 | (d) p = 0, E ¹ 0 |
(b) p ¹ 0, E ¹ 0
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In a full wave rectifiers, input ac current has a frequency ‘n’. The output frequency of current is
|
(a) n/2 |
(b) n |
(c) 2n |
(d) None of these |
It is desired to photograph the image of an object placed at a distance of 3m from the plane mirror. The camera which is at a distance of 4.5 m from the mirror should be focussed for a distance of
| (a) 3m | (b) 4.5m | (c) 6m | (d) 7.5 m |
A heater coil connected to a supply of a 220 V is dissipating some power
The coil is cut into half and the two halves are connected in parallel. The heater now dissipates a power
The ratio of power
is
|
(a) 2 : 1 |
(b) 1 : 2 |
(c) 1 : 4 |
(d) 4 : 1
|
The binding energy per nucleon of
is 7.97 MeV and that of
is 7.75 MeV. The energy (in MeV) required to remove a neutron from
is
|
(a) 3.52 |
(b) 3.64 |
(c) 4.23 |
(d) 7.86 |
A particle of mass M and charge Q moving with velocity
describes a circular path of radius R when subjected to a uniform transverse magnetic field of induction B. The work done by the field when the particle completes one full circle is
|
(a) BQv2πR |
(b) |
(c) Zero |
(d) BQ |
A person can see clearly only upto a distance of 25 cm. He wants to read a book placed at a distance of 50 cm. What kind of lens does he require for his spectacles and what must be its power
|
(a) Concave, – 1.0 D |
(b) Convex, + 1.5 D |
(c) Concave, – 2.0 D |
(d) Convex, + 2.0 D |
Three identical capacitors are given a charge Q each and they are then allowed to discharge through resistance R1, R2 and R3. Their charges, as a function of time shown in the graph below. The smallest of the three resistance is
|
(a) R3 |
(b) R2 |
(c) R1 |
(d) Cannot be predicted |
Emission spectrum of gas
|
(a) Is a line spectrum |
(b) Is a band spectrum |
|
(c) Is a continuous spectrum |
(d) Does not fall in the visible region |