Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

A radio isotope has a half life of 75 years. The fraction of the atoms of this material that would decay in 150 years will be

(a) 66.6%

(b) 85.5%

(c) 62.5%

(d) 75%

The hysteresis cycle for the material of permanent magnet is:

The work done in turning a magnet of magnetic moment 'M' by an angle of 90° from the meridian is 'n' times the corresponding work done to turn it through an angle of 60°, where 'n' is given by

(a) 1/2

(b) 2

(c) 1/4

(d) 1

For a fast chain reaction, the size of U²³⁵ block, as compared to its critical size, must be:

Consider the following statements A to B  and identify the correct answer

A. Polarised light can be used to study the helical surface of nucleic acids.

B. Optics axis is a direction and not any particular line in the crystal

(a) A and B are correct	(b) A and B are wrong
(c) A is correct but B is wrong	(d) A is wrong but B is correct

A charged water drop whose radius is 0.1 μm  is in equilibrium in an electric field. If charge on it is equal to charge of an electron, then intensity of electric field will be (g = 10

(a) 1.61 N/C

(b) 26.2 N/C

(c) 262 N/C

(d) 1610 N/C

Consider a collision between an oxygen molecule and a hydrogen molecule in a mixture of oxygen and hydrogen kept at room temperature. Which of the following are pcssible?

1. The kinetic energies of both the molecules increase.
2. The kinetic energies of both the molecules decrease.
3. The Kinetic energy of the oxygen molecule increases and that of the hydrogen molecule decreases.
4. The kinetic energy of the hydrogen molecule increases and that of the oxygen molecule decreases.

Let n_r and n_b be the number of photons emitted by a red bulb and a blue bulb, respectively, of equal power in a given time:

Gold-leaf electroscope can be used _______?

According to Huygens, the ether medium pervading entire universe is: