Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

The potential energy of a system of two charges is negative when:

When light is incident on a doubly refracting crystal, two refracted rays-ordinary ray (O-ray) and extra ordinary ray (E-ray) are produced. Then

(a) Both O-ray and E-ray are polarised perpendicular to the plane of incidence

(b) Both O-ray and E-ray are polarised in the plane of incidence

(c) E-ray is polarised perpendicular to the plane of incidence and O-ray in the plane of incidence

(d) E-ray is polarised in the plane of incidence and O-ray perpendicular to the plane of incidence

An electron enters between two horizontal plates separated by 2mm and having a potential difference of 1000V. The force on electron is

(a) 8

(b) 8 N

(c) 8

(d) 8

In any fission process the ratio   is

(a) Less than 1

(b) Greater than 1

(c) Equal to 1

(d) Depends on the mass of the parent nucleus

Due to the flow of current in a circular loop of radius R, the magnetic induction produced at the centre of the loop is B. The magnetic moment of the loop is (

(a)

(b)

(c)

(d)

The electrostatic potential on the surface of a charged conducting sphere is 100V. Two statements are made in this regard S₁ at any point inside the sphere, electric intensity is zero. S₂ at any point inside the sphere, the electrostatic potential is 100V. Which of the following is a correct statement?

Two sound waves move in the same direction in the same medium. The pressure amplitudes of the waves are equal but the wavelength of the first wave is double the second. Let the average power transmitted across a cross-section by the first wave be P₁ and that by the 1 second wave be P₂. Then,

1. P₁ = P₂
2. P₁ = 4P₂
3. P₂ = 2P₁
4. P₂ = 4P₁

Resistances  and  are joined in parallel and a current is passed so that the amount of heat liberated is  and   respectively. The ratio   has the value

(a)

(b)

(c)

(d)