Alternating Current — Physics STD 12 Science — Question

The force per unit charge is known as ____________.

Two magnets A and B are identical and these are arranged as shown in the figure. Their length is negligible in comparison to the separation between them. A magnetic needle is placed between the magnets at point P which gets deflected through an angle θ  under the influence of magnets. The ratio of distance   and  will be

(a)

(b)

(c)

(d)

Two plates are 2 cm  apart, a potential difference of 10 volt  is applied between them, the electric field between the plates is

(a) 20 N/C

(b) 500 N/C

(c) 5 N/C

(d) 250 N/C

The centre of mass of a system of particles is at the origin. It follows that:

1. The number of particles to the right of the origin is equal to the number of particles to the left.
2. The total mass of the particles to the right of the origin is same as the total mass to the left of the origin.
3. The number of particles on X-axis should be equal to the number of particles on Y-axis.
4. If there is a particle on the positive X-axis, there must be at least one particle on the negative X-axis.
5. None.

In the following circuit find I₁ and I₂

(a) 0, 0

(b) 5 mA, 5 mA

(c) 5 mA, 0

(d) 0, 5 mA

Magnifying power of a simple microscope is (when final image is formed at D = 25 cm from eye)

(a)

(b) 1 +

(c)

(d)

A 10 pF capacitor is connected to a 50 V battery. How much electrostatic energy is stored in the capacitor

(a) 1.25

(b) 2.5

(c) 3.5

(d) 4.5

The magnetic field at a distance r from a long wire carrying current i is 0.4 Tesla. The magnetic field at a distance 2r is

(a) 0.2 Tesla

(b) 0.8 Tesla

(c) 0.1 Tesla

(d) 1.6 Tesla

When a current passes through the junction of two different  metals, evolution or absorption of heat at the junction is known as

(a) Joule  effect

(b) Seebeck effect

(c) Peltier effect

(d) Thomson effect