1. The unit of noise pollution (level) is :
a) Decibel
b) Decimal
c) ppm
d) None of these
Explanation: Loudness (also called sound pressure level, or SPL) is measured in logarithmic units called decibels (dB).
2. The speed of sound travel fastest through
a) Liquid
b) Solid
c) gas
d) None of the above
Explanation: Of the three phases of matter (gas, liquid, and solid), sound waves travel the slowest through gases, faster through liquids, and fastest through solids.
3. Compressions and Rarefactions are characteristic of
a) Longitudinal waves
b) Transverse waves
c) Both A & B
d) Neither of A & B
Explanation: Compressions and Rarefactions are characteristic of longitudinal waves.
4. Least audible sound for most of the human ear is :
a) 10.0 µ bar
b) 0.0002 µ bar
c) 0.005 µ bar
d) 5.0 µ bar
Explanation: Least audible sound for most of the human ear is 0.0002 µ bar.
5.Hertz is a unit for measuring
a) Intensity of waves
b) Frequency of waves
c) Wavelength
d) Clarity of waves
Explanation: Frequency is the rate at which current changes direction per second. It is measured in hertz (Hz), an international unit of measure where 1 hertz is equal to 1 cycle per second.
6. For which of the following substances, the resistance decreases with increase in temperature?
a) Pure silicon
b) cooper
c) Nichrome
d) Platinum
Explanation: cooper
7. The S.I. unit of electric charge is :
a) Ampere
b) Coulomb
c) e.s.u
d) Kelvin
Explanation: Electric charge has the dimension electric current time. The SI derived unit of electric charge is the coulomb, which is defined as an ampere second.
8. Indicate the false statement about the resistance of a wire
a) It depends on material of wire
b) It is directly proportional to the length of wire
c) It is directly proportional to the area of cross-section of wire
d) Resistance of metallic wire increases with increase in temperature
Explanation: It is directly proportional to the area of cross-section of wire is a false statement.
9. The magnitude of current flowing between two end points of a conductor is proportional to the potential difference between them and is called as:
a) Avogadro's law
b) Rault's law
c) ohm law
d) Faraday's law
Explanation: According to Ohm’s Law, the potential difference (V) between two terminals of a current-carrying conductor is directly proportional to the current (I), flowing through it. The proportionality constant R, is the resistance of the conductor. Thus, V α I
or V = I × R
or I = V/R
or R = V/I.
10. What is the SI unit of electric current?
a) Newton
b) Joule
c) Ampere
d) watt
Explanation: SI unit of electric current is Ampere.