Electric Charges and Fields — Physics STD 12 Science — Question

Assertion : The force of repulsion between atomic nucleus and a-particle varies with distance according to inverse square law. 

Reason     : Rutherford did a-particle scattering experiment.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

A rectangular loop carrying a current i is situated near a long straight wire such that the wire is parallel to the one of the sides of the loop and is in the plane of the loop. If a steady current I is established in wire as shown in figure, the loop will

(a) Rotate about an axis parallel to the wire

(b) Move away from the wire or towards right

(c) Move towards the wire

(d) Remain stationary

The acceleration of an electron in an electric field of magnitude 50 V/cm, if e/m value of the electron is  1.76  is

(a) 8.8  m/sec2

(b) 6.2  m/sec2

(c) 5.4  m/sec2

(d) Zero

A parallel plate condenser is connected with the terminals of a battery. The distance between the plates is 6mm. If a glass plate (dielectric constant K  = 9) of 4.5 mm  is introduced between them, then the capacity will become

(a) 2 times

(b) The same

(c) 3 times

(d) 4 times

During the nuclear fusion reaction

(a) A heavy nucleus breaks into two fragments by itself

(b) A light nucleus bombarded by thermal neutrons breaks up

(c) A heavy nucleus bombarded by thermal neutrons breaks up

(d) Two light nuclei combine to give a heavier nucleus and possibly other products

Because we cannot ever know the initial conditions of groups of objects with perfect precision, the later behaviour of complex systems of objects may be almost completely unpredictable, even the wonderfully successful equations derived from Newtonian mechanics.
The previous statement describes the essence of which theory?

A resistor and an inductor are connected to an ac supply of 120V and 50 Hz. The current in the circuit is 3A. If the power consumed in the circuit is 108W, then the resistance in the circuit is.

Earth’s magnetism was discovered by:

An AC voltmeter in an L - C - R circuit reads 30volt across resistance, 80 volt across inductance and 40 volt across capacitance. The value of applied voltage will be.

Let V and E be the gravitational potential and gravitational field at a distance r from the centre of a uniform spherical shell. Consider the following two statements:

1. The plot of V against r is discontinuous.
2. The plot of E against r is discontinuous.

1. Both A and B are correct.
2. A is correct but B is wrong.
3. B is correct but A is wrong.
4. Both A and B are wrong.