For an electron in H-atom the frequency of photon for transition between levels 1 and 2 is V .The photon frequency for transition between levels 2 and 3 is closest to
A. 0.2V
B. 0.1V
C. V
D. 0.5V
Emission of electrons in photoelectric effect is possible if :
A. metal surface is slightly polished
B. the incident light is of sufficiently high intensity
C. the light is incident at right angles to surface of the metal
D. the incident light is of sufficiently low wavelength
A 2 kg mass moving on a smooth frictioriless surface with a velocity of 10 m/s, hits another 2 kg mass kept at rest in an elastic collision. After collision, if they move together:
A. they travel with a velocity of 5 ms-1 in the same direction
B. they travel with a velocity of 10 ms-1 in the same direction
C. they travel with a velocity of 10 ms-1 in the opposite direction
D. they travel in the opposite direction with a velocity of 5 ms-1