EdgineerX

676. The audible frequency range for a normal human ear is about

A. 1 Hz to 1 kHz B. 200 Hz to 200 kHz C. 20 kHz to 200 kHz D. 20 Hz to 20 kHz E. 2 Hz to 200 Hz

677. Ultrasonic waves are used in medical imaging mainly because they

A. are audible B. cannot be reflected C. have short wavelengths giving good resolution D. travel faster than light E. are ionizing

678. Light from distant galaxies is shifted towards longer wavelengths, which indicates that they are

A. emitting sound B. stationary C. hotter than the Sun D. receding from us E. approaching us

679. A tuning fork of frequency 320 Hz gives 4 beats per second with a second fork. The possible frequencies of the second fork are

A. 318 or 322 Hz B. 160 or 640 Hz C. 4 or 640 Hz D. 312 or 328 Hz E. 316 or 324 Hz

680. Bright fringes in a two slit pattern occur where the path difference is

A. (n + 1/2) lambda B. n lambda C. lambda/4 D. zero only E. 2 lambda only

681. Two coherent sources are most easily obtained in the laboratory by

A. dividing light from a single source B. using two different lasers C. using sunlight directly D. using two separate lamps E. using two different colours

682. Polaroid sunglasses reduce glare because reflected light from horizontal surfaces is

A. monochromatic B. diffracted C. unpolarized D. partially polarized in the horizontal plane E. circularly polarized

683. The colours of a soap bubble are produced by

A. dispersion B. polarization by reflection C. interference in a thin film D. total internal reflection E. scattering of light

684. The overall magnification of a compound microscope is

A. independent of the eyepiece B. the product of the objective and eyepiece magnifications C. equal to the eyepiece magnification D. the ratio of the two magnifications E. the sum of the objective and eyepiece magnifications

685. The power of a lens of focal length 50 cm is

A. 2 dioptre B. 50 dioptre C. 0.5 dioptre D. 0.02 dioptre E. 5 dioptre

686. Astigmatism is corrected using a

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

687. 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

688. 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

689. 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

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

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

691. 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

692. 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

693. 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

694. 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

695. 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

696. 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

697. 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

698. 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

699. 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

700. The heat produced in a resistor is given by

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

Physics