Electromagnetic Induction — Physics STD 12 Science — Question

The optical path of a monochromatic light is same if it goes through 4.0 cm of glass or 4.5 cm of water.  If the refractive index of glass is 1.53, the refractive index of the water is

(a) 1.30

(b) 1.36

(c) 1.42

(d) 1.46

When potential difference is applied across an electrolyte, then Ohm's law is obeyed at:

Two negative charges are kept at a certain distance in the air medium. What will happen if a dielectric slab is inserted between them?

A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will:

Two nucleons are at a separation of 1 fm. The net force between them is F₁​ if both are neutrons, F₂​ if both are protons, and F₃​ if one is a proton and the other is a neutron then:

The current flowing through a lamp marked as 50 W and 250 V is

(a) 5 amp

(b) 2.5 amp

(c) 2 amp

(d) 0.2 amp

The de-Broglie wavelength of a particle accelerated with 150 volt potential is  m. If it is accelerated by 600 volts p.d., its wavelength will be

(a) 0.25 Å

(b) 0.5 Å

(c) 1.5 Å

(d) 2 Å

Serious draw back of the semiconductor device is

(a) They cannot be used with high voltage

(b) They pollute the environment

(c) They are costly

(d) They do not last for long time

Figure represents a graph of kinetic energy (K) of photoelectrons (in eV) and frequency (v) for a metal used as cathode in photoelectric experiment. The work function of metal is

(a) 1 eV

(b) 1.5 eV

(c) 2 eV

(d) 3 eV