# Competitive Exams: Physics MCQs (Practice_Test 28 of 35)

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- Twelve equal wires each of resistance 6 0 form a cube. The resistance between the two diagonally opposite comers will be
- 3 W
- 4 W
- 5 W
- 6 W

- The area of circular coil with 2000 turns is 10 cm2. Its place perpendicular to a magnetic field of 0.3 Wb/m2, is rotated by 180. The change in the magnetic flux is
- 1.2 Wb
- -1.2 Wb
- 0.6 Wb
- -0.6 Wb

- Ratio waves of wavelength 360 m are transmitted from a transmitter. The inductance of the coil which must be connected with a capacitor of capacity 1.2N F in a resonant circuit to receive these waves will be approximately.
- 103H
- 102 H
- l. 0 − 4 H
- 10 − 8H

- Which of the following Law illustrate the fact that the strength of the induced emf developed from a magnetic field depends upon the rate of change of magnetic flux or magnetic induction?
- Faraday՚s law of electromagnetic induction
- Lenz՚s law
- Newman՚s law

Select the correct answer using the codes given below

- 1 alone
- 1,2 and 3
- 2 and 3
- 1 and 3

- The natural frequency of a circuit containing a condenser, resistance and inductance, all in series, is given by Consider the following statements in this regard.
- When R2 > 4L/C the discharge is dead beat or non-oscillatory.
- When R2 = C the discharge is critically damped.
- When R2 < C, the discharge is oscillatory.

Of these statements

- 1,2 and 3 are correct
- 1 and 2 are correct
- 2 and 3 are correct
- 1 and 3 are correct

- Consider the following statements regarding ac circuit having an inductance and a capacitance
- Parallel resonance circuit is used for wireless reception.
- Parallel resonance circuit works as a perfect choke for ac and therefore is called a rejector.
- Series resonance circuits have special importance in transmission systems.
- It, series resonance circuit, current and emf are ire phase and hence called acceptor circuit.

Of those statements

- 1,2 and 4 are correct
- 2,3 and 4 are correct
- 1 and 3 are correct
- 2 and 4 are correct

- Current in a coil of 1.5 H increases as I = 4 sin (2t) amperes. During the time the current changes from 0 to 4 A, the amount of energy spent will be
- 24 J
- 12J
- 8 J
- 6 J