Physics MCQ Questions with Answer for all Competitive Exams
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Physics MCQ Questions with Answer
Q1. Ice is packed in sawdust because
(a) Sawdust does not stick to the ice
(b) Sawdust will not get melt easily
(c) Sawdust is a good conductor of heat
(d) Sawdust is a poor conductor of heat
Answer: (d)
Explanation: Sawdust is a poor conductor of heat. Thus it does not let the atmospheric heat to pass through it and melt the ice.
Q2. Which of the following is the smallest unit of length?
(a) Micrometre
(b) Nanometre
(c) Angstrom
(d) Fermi meter
Answer: (d)
Explanation: 1 micron = 10–6 m
1 nanometre = 10–9 m
1 angstrom = 10–10 m
1 Fermi = 10–15 m
Q3. A simple machine helps a Fenton in doing:
(a) Less work
(b) The same amount of work with lesser force
(c) The same amount of work slowly
(d) The same amount of work much faster
Answer: (b) The same amount of work with lesser force
Explanation: A simple machine is a mechanical device that changes the direction or magnitude of a force. In general, they can be defined as the simplest mechanisms that use mechanical advantage to multiply force. Thus, a simple machine helps us in doing the same amount of work with lesser force. Few examples of simple machines are pulley, lever, wheel, screw, etc.
Q4. Water is used in a car radiator because of its
(a) Low density
(b) Easy availability
(c) High specific heat capacity
(d) Low boiling point
Answer: (c)
Explanation: Water has high specific heat which allows water to draw up more heat from the radiator and hence keeps it cool.
Q5. The working principle of a washing machine is
(a) Centrifugation
(b) Dialysis
(c) Reverse osmosis
(d) Diffusion
Answer: (a)
Explanation: The washing machine works on the principle of centrifugation. Centrifugation is a process that involves the use of the centrifugal force for the separation of mixtures with a centrifuge, used in industry and in laboratory settings. More-dense components of the mixture migrate away from the axis of the centrifuge, while less-dense components of the mixture migrate towards the axis.
Q6. Which one of the following is a vector quantity?
(a) Momentum
(b) Pressure
(c) Energy
(d) Work
Answer: (a)
Explanation: Scalars are quantities that have magnitude only; they are independent of direction. Vectors have both magnitude and direction. Momentum is the product of the mass and velocity of an object (p = mv). Momentum is a vector quantity since it has a direction as well as a magnitude. The rest of the quantities in option pressure, work, and energy has magnitude but not direction.
Q7. Match List-I with List-II and select the correct answer using the codes given below the lists:
List-I
List-II
A. Wavelength
1. Hertz
B. Energy
2. Angstrom
C. Intensity of sound
3. Joule
D. Frequency
4. Decibel
Codes: A B C D
(a) 2 3 4 1
(b) 1 2 3 4
(c) 2 3 1 4
(d) 2 1 3 4
Answer: (a)
Explanation: Wavelength is the distance between two consecutive crests or troughs and 1 angstrom = 10–10 m, a joule is the unit of energy. The intensity of sound is measured in decibel. Frequency is measured in hertz (Hz).
Q8. Alcohol is more volatile than water because ______ is lower than water.
(a) Its boiling point
(b) Its density
(c) Its viscosity
(d) Its surface tension
Answer: (a)
Explanation: Lower the boiling point higher is the volatility. Alcohol has boiling point 78°C whereas the boiling point of water is 100°C.
Q9. What is the correct sequence in which the lengths of the following units increase?
1.Angstrom
2. Micron
3. Nanometre
Select the correct answer using the codes given below:
(a) 1, 2, 3
(b) 3, 1, 2
(c) 1, 3, 2
(d) 2, 3, 1
Answer: (c)
Explanation: The multiplier for the given units are as follows:
1 Angstrom=10–10 m
2 Micron=10–6 m
3 Nanometre= 10–9m
Hence, the order in which the lengths of the given units increase is given by Angstrom, Nanometre, Micron. Therefore, the correct sequence is 1, 3, and 2.
Q10. What is the SI unit of temperature?
(a) Kelvin
(b) Joule
(c) Celsius
(d) Fahrenheit
Answer: (a)
Explanation: S.I. unit of temperature is Kelvin (K) named after Lord Kelvin. The Kelvin is defined as the fraction 1/273.16 of the thermodynamic temperature of the triple point of water (exactly 0.1°C or 32.018°F)
