Physics MCQs Test 9

1. Increase in velocity of sound in the air for a 1°C rise in temperature is_________________?

  • A. 1.61 ms-1
  • B. 61.0 ms-1
  • C. 0.61 ms-1
  • D. 2.00 ms-1
See Answer
C. 0.61 ms-1
2. On loading the prong of a tuning form with wax its frequency____________________?

  • A. increases
  • B. decreases
  • C. remains unchanged
  • D. may increase or decrease
See Answer
B. decreases
3. The normal ear is the most sensitive in the frequency range___________________?

  • A. 20000 to 30000 hertz
  • B. 10 to 20 hertz
  • C. 2000 to 4000 hertz
  • D. 6000 to 8000 hertz
See Answer
C. 2000 to 4000 hertz
4. The velocity of sound in the air would become double its velocity at 0°C at temperature________________?

  • A. 313°C
  • B. 586°C
  • C. 819°C
  • D. 1172°C
See Answer
C. 819°C
5. The periodic alternation of sound between maximum and minimum loudness are called___________________?

  • A. silence zone
  • B. interference
  • C. beats
  • D. resonance
See Answer
C. beats
6. Beats are the results of____________________?

  • A. diffraction of sound waves
  • B. constructive and destructive interference
  • C. polarization
  • D. destructive interference
See Answer
B. constructive and destructive interference
7. Doppler effect applies to____________________?

  • A. sound wave only
  • B. light wave only
  • C. Both sound and light waves
  • D. neither sound nor light wave
See Answer
C. both sound and light waves
8. A simple pendulum has a bob of mass m and its frequency is f. If we replaced the bob with a heavier one say 2m then that will be its new frequency?

  • A. 1/4f
  • B. 1/2f
  • C. frequency lower than 20 Hz
  • D. 2f
See Answer
C. frequency lower than 20 Hz
9. In open organ pipe___________________?

  • A. only even harmonics are present
  • B. only odd harmonics are present
  • C. both even and odd harmonics are present
  • D. selected harmonics are present
See Answer
C. both even and odd harmonics are present
10. The dimension of elastic modulus is ___________________?

  • A. ML-1T-2
  • B. ML-2T-2
  • C. MLT-2
  • D. ML2T-2
See Answer
A. ML-1T-2

11. A completely filled band is called__________________?

  • A. Conduction band
  • B. Valence band
  • C. Forbidden band
  • D. Core band
See Answer
D. Core band
12. Which one has the greatest energy gap?

  • A. Semiconductor
  • B. Conductor
  • C. Metals
  • D. Non-metals
See Answer
D. Non-metals
13. With the increase in temperature the electrical conductivity of intrinsic semiconductor___________________?

  • A. Decreases
  • B. Increases
  • C. Remains same
  • D. First increases then decreases
See Answer
B. Increases
14. Based on the band theory of solids, the semiconductors have _____________________?

  • A. A party-filled valence band and empty conduction band
  • B. A filled valence band an empty conduction band and a very wide forbidden band
  • C. A filled valence band a partially filled conduction band and a narrow forbidden band
  • D. A partly filled valence band an empty conduction band and a wide forbidden band
See Answer
C. A filled valence band a partially filled conduction band and a narrow forbidden band

15. Very weak magnetic fields are detected by___________________?

  • A. Squids
  • B. Magnetic resonance imaging (MRI)
  • C. Magnetometer
  • D. Oscilloscope
See Answer
A. Squids
16. Energy needed to magnetize and demagnetize is represented by _________________?

  • A. Hysteresis curve
  • B. Hysteresis loop area
  • C. Hysteresis loop
  • D. Straight line
See Answer
B. Hysteresis loop area
17. What is the SI unit of modulus of elasticity of substance?

  • A. Nm-2
  • B. Jm-2
  • C. Nm-1
  • D. Being a number it has no unit.
See Answer
A. Nm-2
18. A rubber cord of cross-sectional area 2cm2 has a length of 1m. When a tensile force of 10N is applied the length of the cord increases by 1cm. What is the Youngs modulus of rubber?

  • A. 2×108 Nm-2
  • B. 5×106 Nm-2
  • C. 0.5×10-6 Nm-2
  • D. 0.2×10-6Nm-2
See Answer
B. 5×106 Nm-2
19. A uniform steel wire of length 4m and area of cross-section 3×10-6m2 is extended by 1mm by the application of a force. If the youngs modulus of steel is 2×1011 Nm-2 the energy stored in the wire is___________________?

  • A. 0.025J
  • B. 0.50J
  • C. 0.75J
  • D. 0.100J
See Answer
C. 0.75J
20. Materials that undergo plastic deformation before breaking are called __________________?

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