Current Electricity — Physics STD 12 Science — Question

Figure shows a smooth inclined plane fixed in a car accelerating on a horizontal road. The angle of incline 0 is related to the acceleration a of the car as a = g tan°. If the sphere is set in pure rolling on the incline:

1. It will continue pure rolling.
2. It will slip down the plane.
3. Its linear velocity will increase.
4. Its linear velocity will slowly decrease.

The motion of electron inside the conductor is :

Which of the following is not electromagnetic wave ?

Out of the following, which colour's wavelength is more than the wavelength of yellow colour?

Four lowest energy levels of H-atom are shown in the figure. The number of possible emission lines would be

(a) 3

(b) 4

(c) 5

(d) 6

The de-Broglie wavelength of electron in 3^rd orbit of He⁺¹ ion is approximately.

Plane figures made of thin wires of resistance R = 50 milli ohm/metre are located in a uniform magnetic field perpendicular into the plane of the figures and which decrease at the rate dB/dt = 0.1 m T/s. Then currents in the inner and outer boundary are. (The inner radius a = 10 cm and outer radius b = 20 cm)

(a) 10– 4 A (Clockwise), 2 × 10– 4 A (Clockwise)

(b) 10– 4 A (Anticlockwise), 2 × 10– 4 A (Clockwise)

(c) 2 × 10– 4 A (clockwise), 10– 4 A (Anticlockwise)

(d) 2 × 10– 4 A (Anticlockwise), 10– 4 A (Anticlockwise)

The value of electric permittivity of free space is:

An electron jumps from 5^th orbit to 4^th orbit of hydrogen atom. Taking the Rydberg constant as  per metre. What will be the frequency of radiation emitted

(a) 6.75

(b) 6.75

(c) 6.75

(d) None of these

Two concentric coplanar circular loops of radii  and  carry currents of respectively  and  in opposite directions (one clockwise and the other anticlockwise.) The magnetic induction at the centre of the loops is half that due to  alone at the centre. If .  the value of   is

(a) 2

(b) 1/2

(c) 1/4

(d) 1