Model Paper 1 — Physics STD 12 Science — Question

The expected energy of the electrons at absolute zero is called

(a) Fermi energy

(b) Emission energy

(c) Work function

(d) Potential energy

A straight conductor of length 0.4 m is moved with a speed of 7 m/s perpendicular to the magnetic field of intensity of 0.9 Wb/m². The induced e.m.f. across the conductor will be

(a) 7.25 V

(b) 3.75 V

(c) 1.25 V

(d) 2.52 V

The potential difference across the 100 W resistance in the following circuit is measured by a voltmeter of 900 W resistance. The percentage error made in reading the potential difference is

(a)

(b) 0.1

(c) 1.0

(d) 10.0

The region of the atmosphere above troposphere is known as

(a) Lithosphere

(b) Uppersphere

(c) Ionosphere

(d) Stratosphere

A very long bar magnet is placed with its north pole coinciding with the centre of a circular loop carrying as electric current i. The magnetic field due to the magnet at a point on the periphery of the wire is B. The radius of the loop is a. The force on the wire is:

Assertion :   Through the same current flows through the line wires and the filament of the bulb but heat produced in the filament is much higher then that in line wires.

Reason     : The filament of bulbs is made of a material of high resistance and high melting point.

(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 network of four capacitors of capacity equal to   and   are conducted in a battery as shown in the figure. The ratio of the charges on   and   is

(a)

(b)

(c)

(d)

Nuclear forces exists between:

Critical angle of light passing from glass to air is minimum for

(a) Red

(b) Green

(c) Yellow

(d) Violet