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Showing 826 to 850 of 1648 questions (page 34 of 66).

826. The SI unit of magnetic flux is

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

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

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

828. 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 loop area D. the enclosed charge E. the flux through the loop

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

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

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

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

831. The SI unit of self inductance is

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

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

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

833. In a step up transformer

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

834. Eddy currents in transformer cores are reduced by

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

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

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

836. The resonant frequency of a series LC circuit is

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

837. The capacitive reactance of a capacitor

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

838. In a purely inductive AC circuit, the current

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

839. The speed of electromagnetic waves in free space is

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

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

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

841. The SI unit of Young's modulus is

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

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

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

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

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

844. Above the Curie temperature, a ferromagnetic material becomes

A. more strongly ferromagnetic B. non-magnetic in the sense of losing all response C. superconducting D. diamagnetic E. paramagnetic

845. Stress within the elastic limit is

A. zero B. inversely proportional to strain C. directly proportional to strain D. proportional to the square of strain E. independent of strain

846. A p-n junction diode conducts appreciably when

A. at absolute zero B. forward biased C. unbiased D. the depletion region widens E. reverse biased

847. The output ripple frequency of a full wave rectifier fed from a 50 Hz supply is

A. 100 Hz B. 150 Hz C. 50 Hz D. 25 Hz E. zero

848. A Zener diode in a voltage regulator circuit is operated in

A. the cut off region B. forward bias C. the saturation region D. reverse bias beyond the breakdown voltage E. zero bias

849. Which logic gate is called a universal gate?

A. XOR B. NAND C. AND D. NOT E. OR

850. In an ideal operational amplifier, the input impedance and open loop gain are respectively

A. zero and zero B. finite and unity C. infinite and infinite D. infinite and zero E. zero and infinite

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