Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and all one day examinations of India.
1. Which of the following is responsible for the fact that Tennis ball bounces higher at high altitudes than in plains?
[A] Low Gravity
[B] High Gravity
[C] Less dense air
[D] Low atmospheric temperature
Show Answer
Correct Answer: C [ Less dense air ]
Notes:
The rarified air at high altitudes gives less resistance to ball.
2. The X-ray crystallography mainly uses which among the following properties of electromagnetic radiation?
[A] Reflection
[B] Diffraction
[C] Interference
[D] Refraction
Show Answer
Correct Answer: B [ Diffraction]
Notes:
X-ray crystallography helps to determine the atomic and molecular structure of a crystal. The crystalline structure performs the diffraction and it causes a beam of incident X-rays to diffract into many specific directions.
3. The pointer or arrow of the magnetized needle of a compass indicates which among the following?
[A] Geographic North Pole
[B] Magnetic North Pole
[C] Geo-magnetic North Pole
[D] Magnetic South Pole
Show Answer
Correct Answer: D [ Magnetic South Pole]
Notes:
The north pole of a magnet in a compass points north because it is attracted to the Earth’s magnetic south pole, which is located near Earth’s geographic north pole. The geographic north pole of earth corresponds to magnetic south pole and geographic south pole of earth corresponds to magnetic north pole. The direction in which a compass needle points is known as magnetic north. This is not exactly the direction of the North Magnetic Pole. Instead, the compass aligns itself to the local geomagnetic field, which varies in a complex manner over the Earth’s surface. The angular difference between magnetic north and true north (defined in reference to the Geographic North Pole), at any particular location on the Earth’s surface, is called the magnetic declination. Most map coordinate systems are based on true north, and magnetic declination is often shown on map legends so that the direction of true north can be determined from north as indicated by a compass.
4. Which of the following makes a CD or DVD show rainbow pattern?
[A] Diffraction of the Light
[B] Thin-Film Interference of the light
[C] Scattering of the light
[D] Polarisation of the light
Show Answer
Correct Answer: A [ Diffraction of the Light]
Notes:
A CD or DVD has closely spaced tracks which work as a diffraction grating to form the familiar rainbow pattern seen when looking at a disk.
5. Which of the following statements is correct?
[A] The acceleration due to gravity is same at the equator and the poles
[B] The acceleration due to gravity is maximum at the poles
[C] The acceleration due to gravity is least at the poles
[D] None of the above
Show Answer
Correct Answer: B [The acceleration due to gravity is maximum at the poles]
Notes:
The acceleration due to gravity is maximum at the poles and is least at the equator. The value of acceleration due to gravity increases as we go from the equator to the pole.
6. Which of the following has an effect on the value of acceleration due to gravity?
[A] Shape of the earth
[B] Height above the earth surface
[C] Axial rotation of the earth
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
The value of acceleration due to gravity vary due to the following factors : (a) Shape of the earth (b) Height above the earth surface (c) Depth below the earth surface (d) Axial rotation of the earth
7. What is Young’s Modulus?
[A] ratio of longitudinal strain to normal stress
[B] product of normal stress of longitudinal strain
[C] ratio of normal stress to longitudinal strain
[D] ratio of normal stress to lateral strain
Show Answer
Correct Answer: C [ratio of normal stress to longitudinal strain]
Notes:
Young’s Modulus is defined as the ratio of normal stress to longitudinal strain within limit of proportionality. Y = normal stress/longitudinal strain
8. Which of the following has no effect on the pressure beneath the surface of a liquid?
[A] Area of the liquid surface
[B] Density of the liquid
[C] Strength of the gravitational field
[D] Depth of the liquid
Show Answer
Correct Answer: A [Area of the liquid surface]
Notes:
Pwater = ⍴gh It is clear from the above formula that water pressure only depends on density of water, gravitational acceleration and height of water column.
9. What is the main cause of capillarity?
[A] difference in weight of fluids
[B] pressure difference
[C] temperature difference
[D] velocity gradient
Show Answer
Correct Answer: B [pressure difference]
Notes:
The main cause of capillarity is the difference in pressures on two sides of (concave and convex) curved surface of liquid.
10. What is the relationship between excess pressure and the radius of the bubble?
[A] are equal in value
[B] inversely proportional to each other
[C] directly proportional to each other
[D] no relationship
Show Answer
Correct Answer: B [inversely proportional to each other]
Notes:
Excess pressure is inversely proportional to the radius of bubble (or drop). It means that the pressure inside a smaller bubble is higher than inside a larger bubble.
