Correct Answer: B. increase the sensitivity of the galvanometer

Explanation

Sensitivity of a galvanometer increases when number of turns, area of coil and magnetic field increase

Correct Answer: A. graphite rods

Explanation

Moderation is the process of the reduction of the initial high speed (high kinetic energy) of the free neutron. Since energy is conserved, this reduction of the neutron speed takes place by transfer of energy to a material called a moderator. There are several different types of moderating materials, and each have places where they are used more effectively. Typically-used moderator materials include heavy water, light water, and graphite.

Correct Answer: D. attract each other

Explanation

Two conductors with current flowing in the same direction will attract.

Correct Answer: B. The electric potential energy of a negatively charged particle increases when it moves to a point of lower potential .

Explanation

The potential energy for a positive charge increases when it moves against an electric field. And decreases when it moves with the electric field; The opposite is true for a negative charge. Unless the unit charge crosses a changing magnetic field, its potential at any given point does not depend on the path taken.

Explanation

(a) S.l unite for the intensity of a blackbody radiation = Wm-² OR Js\(^{-1}\)m-²

(b) Two features of the graph

i. The shape of the graph is non-symmetric.

ii. Peaks of the intensity have lower wavelengths/Peaks decrease with wavelength.

iii. The line joining the peaks have a negative gradient.

Correct Answer: A. ferrite substance

Explanation

Ferrite magnets are non-conductive aferromagnetic ceramic compounds derived from iron oxides such as Haematite (Fe203) or Magnetite (Fe304) and other metal oxides such as Barium and Strontium. Ferrite is a polycrystal, sintered material with high electrical resistivity. The high resistance of ferrite makes eddy current losses extremely low at high frequencies.

Explanation

Properties of intrinsic semiconductors. They;

i. Are tetravalent

ii. Have thermally generated charge cariers

iii. Have equal number of charge carriers

iv Have low electrical conductivity/high resistivity.

Correct Answer: A. photoelectric effect

Explanation

The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material.

Correct Answer: D. melting point

Explanation

Internal energy is affected by factors such as pressure, volume, and temperature. All of the variables in this list are state functions. Mass, volume, pressure, temperature, density, and entropy are all examples of state functions.

Correct Answer: C. 40N

Explanation

VR = 5:1 or 5

Load = 20kg or 200N

MA = \(\frac{200}{E}\)

Efficiency% = \(\frac{MA}{VR} * 100\)

100% = \(\frac{200}{5E} * 100\)

5E = 200

E = 40