Physics

Free set

Showing 476 to 500 of 1648 questions (page 20 of 66).

476. A Wheatstone bridge is balanced when

A. the galvanometer reads maximum B. R1 R3 = R2 R4 C. R1/R2 = R3/R4 D. R1 R2 = R3 R4 E. R1 + R2 = R3 + R4

477. The resistance of a thermistor with a negative temperature coefficient

A. becomes zero at 0 K B. increases with temperature C. varies linearly with current D. is independent of temperature E. decreases with temperature

478. Maximum power is delivered by a cell of emf E and internal resistance r to an external resistance R when

A. R is infinite B. R = r/2 C. R = r D. R = 2r E. R = 0

479. The specific resistance of a conductor depends on

A. the current through it B. the nature of the material and temperature C. its length D. its area of cross section E. its shape

480. Two resistances of 6 ohm and 3 ohm are connected in parallel. The equivalent resistance is

A. 4.5 ohm B. 18 ohm C. 9 ohm D. 2 ohm E. 3 ohm

481. The force on a charge q moving with velocity v at angle theta to a magnetic field B is

A. qvB sin theta B. qvB cos theta C. qvB tan theta D. qB/v E. qv/B

482. The magnetic field inside a long solenoid with n turns per unit length carrying current I is

A. mu_0 I B. mu_0 I / n C. mu_0 n / I D. n I / mu_0 E. mu_0 n I

483. The SI unit of magnetic flux is

A. weber B. ampere turn C. tesla D. henry E. gauss

484. A charged particle moving parallel to a uniform magnetic field experiences a force of

A. half the maximum B. qvB C. qE D. zero E. maximum magnitude

485. Ampere's circuital law relates the line integral of the magnetic field around a closed loop to

A. the emf induced B. the enclosed current C. the flux through the loop D. the enclosed charge E. the loop area

486. Lenz's law is a consequence of the conservation of

A. mass B. charge C. energy D. momentum E. flux

487. The motional emf induced in a rod of length l moving with velocity v perpendicular to a magnetic field B is

A. Bv/l B. Bl/v C. B2vl D. Bvl E. B/vl

488. The SI unit of self inductance is

A. farad B. henry C. tesla D. ohm E. weber

489. The energy stored in an inductor of inductance L carrying current I is

A. LI B. L/I2 C. LI2 D. (1/2)LI E. (1/2)LI2

490. In a step up transformer

A. the secondary has more turns than the primary B. the secondary has fewer turns than the primary C. the secondary voltage is lower D. the secondary current is greater E. power in the secondary exceeds that in the primary

491. Eddy currents in transformer cores are reduced by

A. increasing the frequency B. removing the core C. using a solid iron core D. using a copper core E. laminating the core

492. The root mean square value of an alternating current of peak value I_0 is

A. I_0/2 B. sqrt(2) I_0 C. I_0/sqrt(2) D. I_0 E. 2 I_0 / pi

493. The resonant frequency of a series LC circuit is

A. 1/(2 pi sqrt(LC)) B. 1/(2 pi LC) C. 2 pi LC D. sqrt(LC) E. 2 pi sqrt(LC)

494. The capacitive reactance of a capacitor

A. is zero at all frequencies B. decreases with frequency C. increases with frequency D. is independent of frequency E. equals the resistance

495. In a purely inductive AC circuit, the current

A. leads by 45 degrees B. leads the voltage by 90 degrees C. is zero D. lags the voltage by 90 degrees E. is in phase with the voltage

496. The speed of electromagnetic waves in free space is

A. 3 x 10^10 m s-1 B. 332 m s-1 C. 1.5 x 10^8 m s-1 D. 3 x 10^8 m s-1 E. 3 x 10^6 m s-1

497. The power factor of a purely resistive AC circuit is

A. infinite B. 1 C. 0.5 E. 0.707

498. The SI unit of Young's modulus is

A. N m-1 B. N m C. N m-2 D. N m2 E. dimensionless

499. A solid in which the atoms have no long range order is called

A. amorphous B. ferromagnetic C. isomorphic D. polymeric E. crystalline

500. In an insulator, the energy gap between the valence and conduction bands is

A. negative B. about 0.7 eV C. about 1.1 eV D. zero E. greater than about 5 eV

Previous 1 2 … 18 19 20 21 22 … 65 66 Next

Get full access to the MCQ bank

Premium questions, timed mock tests, and detailed explanations.

See premium plans