EdgineerX

1526. SONAR is used to determine the depth of the sea using

A. ultrasonic waves and their echo time B. radio waves C. visible light D. infrasonic waves only E. gamma rays

1527. The principle of superposition states that where two waves meet, the resultant displacement is

A. the product of the individual displacements B. the algebraic sum of the individual displacements C. the difference of the amplitudes only D. the larger of the two displacements E. always zero

1528. If the tension in a stretched string is made four times, the fundamental frequency becomes

A. unchanged B. four times C. double D. one quarter E. half

1529. Diffraction effects are most noticeable when the size of the obstacle or aperture is

A. much larger than the wavelength B. much smaller than the wavelength in every dimension C. independent of the wavelength D. equal to the amplitude E. comparable to the wavelength

1530. In a diffraction grating with more lines per centimetre, the diffracted orders become

A. identical to interference fringes B. more widely separated C. closer together D. independent of wavelength E. less intense only

1531. A magnifying glass produces an image that is

A. real and inverted B. virtual and diminished C. virtual, erect and magnified D. always at the focus E. real and diminished

1532. A telescope is said to be in normal adjustment when the final image is formed

A. at infinity B. at the focal point of the objective C. at the near point D. at the objective E. on the retina directly

1533. A spectrometer is used to

A. measure current B. magnify small objects C. detect magnetic fields D. measure resistance E. disperse light and measure wavelengths

1534. The entropy of a substance during melting at its melting point

A. decreases B. becomes negative C. becomes zero D. increases E. remains constant

1535. A diesel engine is generally more efficient than a petrol engine because it operates with a

A. spark plug B. higher compression ratio C. lower compression ratio D. richer fuel mixture E. lower peak temperature

1536. An ideal gas is compressed adiabatically. Its temperature

A. becomes zero B. stays constant C. falls D. first rises then falls E. rises

1537. Heat supplied to a gas at constant pressure is used to

A. increase the internal energy and do external work B. increase the pressure only C. do external work only D. lower the temperature E. increase the internal energy only

1538. The electric flux through a surface of area A held at angle theta to a uniform field E is

A. EA B. EA sin theta C. EA tan theta D. E/A cos theta E. EA cos theta

1539. Charge on an irregularly shaped conductor accumulates most densely

A. inside the conductor B. uniformly everywhere C. at sharply curved regions and points D. at flat regions E. at the centre of mass

1540. The potential energy of two point charges q1 and q2 separated by r is

A. zero B. k q1 q2 divided by r C. k q1 divided by q2 r D. k q1 q2 divided by r squared E. k q1 q2 times r

1541. In a cathode ray tube, electrons are produced by

A. radioactive decay B. field ionization of the gas C. photoelectric emission from the anode D. secondary emission at the screen E. thermionic emission from a heated filament

1542. A 100 W bulb operated for 10 hours consumes

A. 0.1 kWh B. 1 kWh C. 100 kWh D. 1000 kWh E. 10 kWh

1543. The resistance of a metallic conductor at temperature t is related to its resistance at 0 degrees Celsius by

A. R = R0 alpha t B. R = R0 (1 - alpha t) C. R = R0 (1 + alpha t) D. R = alpha t E. R = R0 divided by alpha t

1544. A cell of emf 2 V and internal resistance 0.5 ohm delivers current to a 1.5 ohm external resistor. The current is

A. 1 A B. 2 A C. 1.33 A D. 4 A E. 0.5 A

1545. Kirchhoff's second rule is based on the conservation of

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

1546. Magnetic flux density is defined as the

A. force per unit charge B. flux per unit area perpendicular to the field C. current per unit area D. flux times area E. flux per unit length

1547. A mass spectrometer separates ions according to their

A. speed only B. colour C. mass to charge ratio D. temperature E. chemical reactivity

1548. The magnetic dipole moment of a coil of N turns, area A, carrying current I is

A. N I A squared B. I A divided by N C. N I divided by A D. N I A E. N A divided by I

1549. Thomson's experiment on the deflection of cathode rays determined the

A. charge to mass ratio of the electron B. mass of the proton C. Planck constant D. charge of the electron E. radius of the atom

1550. A DC generator differs from an AC generator in that it uses

A. no coil B. a capacitor C. a split ring commutator D. no magnet E. slip rings

Physics