EdgineerX

1126. Magnetic flux density is defined as the

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

1127. A mass spectrometer separates ions according to their

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

1128. 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

1129. Thomson's experiment on the deflection of cathode rays determined the

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

1130. A DC generator differs from an AC generator in that it uses

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

1131. In an ideal transformer, the quantity that is the same in the primary and secondary is the

A. voltage B. current C. resistance D. number of turns E. power

1132. An induction furnace melts metal by means of

A. friction B. chemical reaction C. radiation from a filament D. heat generated by eddy currents induced in the charge E. conduction from a flame

1133. The direction of an induced current is such that its magnetic effect

A. is zero B. reverses the magnet polarity permanently C. is perpendicular to the flux D. assists the flux change producing it E. opposes the flux change producing it

1134. In order of increasing wavelength, the correct sequence is

A. radio waves, visible, X-rays, gamma rays B. gamma rays, X-rays, visible, radio waves C. radio waves, infrared, visible, X-rays D. visible, X-rays, gamma rays, radio waves E. infrared, visible, radio waves, gamma rays

1135. A device that converts direct current into alternating current is called

A. a filter B. a transformer C. an inverter D. an amplifier E. a rectifier

1136. An alternating voltage has an rms value of 220 V. Its peak value is about

A. 110 V B. 156 V C. 440 V D. 311 V E. 220 V

1137. The stress beyond which a material no longer returns to its original shape is the

A. elastic limit B. breaking stress C. ultimate tensile stress D. yield strain E. shear stress

1138. A ferromagnetic material owes its strong magnetism to

A. the alignment of magnetic domains B. lattice vibrations C. nuclear spin D. free electrons only E. its high density

1139. A transistor used as a switch operates between

A. the active region and cut off B. cut off and saturation C. saturation and breakdown D. two active points E. reverse and forward breakdown

1140. Besides NAND, the other gate that is universal is

A. AND B. NOT C. XOR D. OR E. NOR

1141. A capacitor placed across the output of a rectifier acts as

A. a switch B. an amplifier C. a rectifier D. a smoothing filter E. an oscillator

1142. According to special relativity, the mass of a body moving at speed comparable to that of light

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

1143. An electron microscope achieves higher resolution than an optical microscope because electrons have

A. a much shorter de Broglie wavelength B. a larger amplitude C. no charge D. greater mass E. a lower speed

1144. The value of Planck's constant is about

A. 6.63 x 10^-27 J s B. 6.63 x 10^-34 J s C. 9.1 x 10^-31 J s D. 3 x 10^8 J s E. 1.6 x 10^-19 J s

1145. A major limitation of Bohr's model is that it

A. ignores the nucleus B. explains the hydrogen spectrum C. predicts continuous spectra D. cannot account for the spectra of multi-electron atoms or fine structure E. requires quantized angular momentum

1146. X-rays are used in industry chiefly for

A. cooling engines B. welding metals C. generating electricity D. measuring temperature E. detecting flaws and cracks inside castings

1147. The wavelength of a spectral line is related to the wave number by

A. wave number equals h divided by the wavelength B. wave number equals the wavelength C. wave number equals the reciprocal of the wavelength D. wave number equals the wavelength squared E. wave number equals c times the wavelength

1148. The radius of a nucleus is of the order of

A. 10^-6 m B. 10^-10 m C. 10^-15 m D. 10^-3 m E. 10^-20 m

1149. A Geiger Muller counter detects radiation by

A. weighing the sample B. registering the ionization pulse produced in a gas C. photographing the track D. measuring the temperature rise E. measuring the magnetic deflection

1150. The most effective general precaution against exposure to ionizing radiation is to

A. use a stronger source B. increase the exposure time C. hold the source in the hand D. work without monitoring E. maximize the distance and use suitable shielding

Physics