Electronics — Physics STD 12 Science — Question

In the options below which one of the isotope of the uranium can cause fission reaction?

If the potential difference applied to an X-ray tube is increased, then for the emitted radiation :

The dimensions of electric flux are:

Cathode rays are produced when the pressure is of the order of(a) 2 cm of Hg(b) 0.1 cm of Hg(c) 0.01 mm of Hg(d) 1 μm of Hg

Assertion :   Electric conduction in gases is possible at normal pressure.
Reason     : The electric conduction in gases depends only upon the potential difference between the electrodes.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

The antenna current of an AM transmitter is 8 A when only carrier is sent but increases to 8.96 A when the carrier is sinusoidally modulated. The percentage modulation is (a) 50%   (b) 60%(c) 65%   (d) 71%

When a metal is illuminated with light wave, then the minimum energy required to take an electron just out of the surface of the metal is called :

What is the unit for EMF?

A plano-convex lens is made of refractive index of 1.6. The radius of curvature of the curved surface is 60 cm. The focal length of the lens is(a) 400 cm(b) 200 cm(c) 100 cm(d) 50 cm