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Showing 1226 to 1250 of 3046 questions (page 50 of 122).

1226. Astigmatism is corrected using a

A. plane mirror B. convex lens C. bifocal lens D. cylindrical lens E. concave lens

1227. Two bodies in thermal equilibrium with a third body are in thermal equilibrium with each other. This statement is the

A. law of heat exchange B. zeroth law of thermodynamics C. first law D. third law E. second law

1228. The specific heat capacity of a substance is the heat required to raise the temperature of

A. unit mass by 1 K B. one mole by 1 K C. the whole body by 1 K D. unit mass by 100 K E. unit volume by 1 K

1229. The latent heat of fusion of ice is about

A. 4.18 J g-1 B. 33.6 J g-1 C. 336 J g-1 D. 2260 J g-1 E. 100 J g-1

1230. A Carnot engine working between 400 K and 300 K has an efficiency of

A. 30% B. 33% C. 75% D. 20% E. 25%

1231. According to the Kelvin statement of the second law, it is impossible to construct an engine that

A. rejects heat to a sink B. converts all the heat absorbed from a single reservoir into work C. uses a gas as working substance D. has an efficiency of 50 per cent E. operates in a cycle

1232. Electric charge exists only in integral multiples of the electronic charge. This is called

A. the superposition principle B. Gauss's law C. conservation of charge D. quantization of charge E. Coulomb's law

1233. Two electric field lines can never intersect because

A. the field would be zero there B. the field would have two directions at one point C. the lines are imaginary D. charges repel E. the field is conservative

1234. The force between two charges of 1 coulomb each placed 1 metre apart in vacuum is

A. 1 N B. 9 x 10^-9 N C. 9 x 10^9 N D. 8.85 x 10^-12 N E. 1.6 x 10^-19 N

1235. For capacitors connected in series, the quantity that is the same on each is the

A. stored energy B. dielectric constant C. capacitance D. potential difference E. charge

1236. The relation between electric field intensity and potential is

A. E = V/r2 B. E = dV/dr times r2 C. E = V r D. E = -dV/dr E. V = E r2

1237. Two resistors of 4 ohm and 6 ohm are joined in series across a 20 V supply. The current is

A. 5 A B. 0.5 A C. 2 A D. 10 A E. 1.2 A

1238. An ideal ammeter and an ideal voltmeter have respectively

A. zero and zero resistance B. zero and infinite resistance C. equal finite resistances D. infinite and zero resistance E. infinite and infinite resistance

1239. A galvanometer is converted into an ammeter by connecting

A. a diode in parallel B. a capacitor in series C. a high resistance in series D. an inductor in series E. a low resistance in parallel

1240. The heat produced in a resistor is given by

A. I2Rt B. I2R/t C. IRt2 D. IR2t E. IRt

1241. The resistance of a conductor of length L, area of cross section A and resistivity rho is

A. rho L A B. A / rho L C. L / rho A D. rho L / A E. rho A / L

1242. In the resistor colour code, the fourth band indicates

A. the multiplier B. the first digit C. the temperature coefficient D. the tolerance E. the power rating

1243. The magnetic field at a perpendicular distance r from a long straight wire carrying current I is

A. mu_0 I / (2r) B. mu_0 I / (2 pi r) C. mu_0 I r D. mu_0 I / r2 E. 2 pi mu_0 I r

1244. The force on a 2 m length of wire carrying 3 A placed perpendicular to a 0.5 T field is

A. 6 N B. 12 N C. 3 N D. 1.5 N E. 0.75 N

1245. A loudspeaker converts electrical energy into sound using

A. the photoelectric effect B. electrostatic attraction C. thermal expansion D. piezoelectric heating only E. the force on a current carrying coil in a magnetic field

1246. A diamagnetic substance in a magnetic field is

A. weakly repelled B. weakly attracted C. strongly attracted D. unaffected E. permanently magnetized

1247. Flux linkage through a coil of N turns each enclosing flux Phi is

A. N/Phi B. N Phi C. N2 Phi D. Phi E. Phi/N

1248. A generator converts

A. chemical to electrical energy B. light to electrical energy C. heat to electrical energy D. mechanical energy to electrical energy E. electrical energy to mechanical energy

1249. Self induction in a coil always

A. opposes the change in current B. assists the change in current C. increases the resistance D. stops the current E. reverses the current

1250. A transformer with 500 primary turns and 2500 secondary turns supplying 220 V to the primary gives a secondary voltage of

A. 2500 V B. 220 V C. 44 V D. 550 V E. 1100 V

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