Magnetism and Matter — Physics STD 12 Science — Question

The mass defect in a particular nuclear reaction is 0.3 grams. The amount of energy liberated in kilowatt hours is (Velocity of light = 3)

(a) 1.5

(b) 2.5

(c) 3

(d) 7.5

The e.m.f. of a cell is E volts and internal resistance is r ohm. The resistance in external circuit is also r ohm. The p.d. across the cell will be

(a) E/2

(b) 2E

(c) 4E

(d) E/4

Assertion  :  The unpolarised light and polarised light can be distinguished from each other by using polaroid.

Reason      : A polaroid is capable of producing plane polarised beams of light.

(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.

How much work is required to carry a 6 mC charge from the negative terminal to the positive terminal of a 9 V battery

(a) 54 ×  J

(b) 54 ×  J

(c) 54 ×

(d) 54 ×  J

An aeroplane in which the distance between the tips of wings is 50 m is flying horizontally with a speed of 360 km/hr over a place where the vertical components of earth magnetic field is 2.0 . The potential difference between the tips of wings would be

(a) 0.1 V

(b) 1.0 V

(c) 0.2 V

(d) 0.01 V

In the figure a carbon resistor has bands of different colours on its body as mentioned in the figure.  The value of the resistance is

(a) 2.2 k W

(b) 3.3 k W

(c) 5.6 k W

(d) 9.1 k W

At a certain place the horizontal component of the earth’s magnetic field is B₀ and the angle of dip is 45^o. The total intensity of the field at that place will be

(a) B0

(b)

(c) 2B0

(d)

The transition from the state n = 4 to n = 3 in a hydrogen like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from:

Which of the following statement(s) is/ are correct?