Physics 11th Chap 13 : Topic 4 - Maryam Publications

Physics Chapter 13 : Topic 4

Postulates of Special Relativity

1 / 30

Special theory of relativity was proposed by:

A) Albert Einstein

B) Galileo Galilei

C) James Clerk Maxwell

D) Isaac Newton

2 / 30

The first postulate of special relativity states that:

A) The laws of physics are the same in all inertial frames.

B) Mass is independent of energy.

C) The speed of light is different for different observers.

D) Time is absolute for all observers.

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An inertial reference frame is one that:

A) is moving with constant velocity or at rest

B) is accelerating continuously

C) has changing direction of motion

D) is rotating with constant speed

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According to the first postulate of special relativity, an observer in an inertial frame:

A) Can perform physics experiments without detecting uniform motion.

B) Cannot measure time.

C) Must always observe Earth at rest.

D) Measures different laws of physics.

5 / 30

The second postulate of special relativity states that:

A) Light speed depends on the source motion.

B) The speed of light in vacuum is constant for all inertial observers.

C) Light requires a medium for propagation.

D) Gravity changes the speed of light.

6 / 30

According to Einstein’s second postulate, the speed of light in vacuum is:

A) $\mathbf{3 \times}\mathbf{10}^{\mathbf{7}}\mathbf{\ m/s}$

B) $\mathbf{3 \times}\mathbf{10}^{\mathbf{8}}\mathbf{\ m/s}$

C) Variable depending on observer motion

D) $\mathbf{3 \times}\mathbf{10}^{\mathbf{6}}\mathbf{\ m/s}$

7 / 30

Einstein’s first postulate rejects the idea of:

A) A preferred inertial frame

B) Electromagnetic waves

C) Mass-energy equivalence

D) Conservation of energy

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If a spacecraft moves at constant velocity relative to Earth, the spacecraft frame is:

A) Non-inertial

B) Inertial

C) Rotating

D) Accelerating

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According to special relativity, the speed of light does not depend on:

A) The value of $\mathbf{c}$

B) Vacuum conditions

C) The medium

D) The observer’s velocity

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A person moving toward a light source measures the speed of light as:

A) Equal to the speed of the observer

B) Less than $\mathbf{c}$

C) Greater than $\mathbf{c}$

D) Equal to $\mathbf{c}$

11 / 30

The first postulate is also known as the principle of:

A) Relativity

B) Superposition

C) Conservation of energy

D) Equivalence of inertial frames

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Einstein introduced special relativity mainly to explain situations involving:

A) Thermal expansion

B) Objects moving at very low speeds

C) Static objects only

D) Objects moving close to the speed of light

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Which statement agrees with Einstein’s first postulate?

A) Only Earth is a valid reference frame.

B) Laws of physics change from one inertial frame to another.

C) All inertial observers measure identical physical laws.

D) Time is always absolute.

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The constancy of the speed of light means:

A) Light speed depends on wavelength only.

B) Light stops when the observer moves.

C) Light always travels with the source velocity.

D) All observers measure the same value of light speed.

15 / 30

The two postulates of special relativity are based on:

A) Inertial frames and constant light speed

B) Gravity and acceleration

C) Electric fields and magnetic fields only

D) Heat and energy transfer

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Which of the following frames is NOT covered by special relativity?

A) A train moving at constant velocity

B) A spacecraft moving uniformly

C) A rotating platform

D) A stationary laboratory

17 / 30

Einstein’s second postulate contradicts the classical idea of:

A) Conservation of charge

B) Addition of velocities

C) Newton’s third law

D) Conservation of momentum

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According to special relativity, the laws of physics are:

A) Identical in all inertial frames

B) Valid only on Earth

C) Different in different inertial frames

D) Dependent on the observer’s location only

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If two observers move relative to each other with constant velocity, they:

A) Must experience acceleration

B) Are both valid inertial observers

C) Cannot apply the laws of physics

D) Measure different speeds of light

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A major consequence of Einstein’s postulates is that:

A) Light requires ether

B) Time and space become relative

C) Mass is always constant

D) Motion has no effect on measurements

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Which experiment supported Einstein’s idea that there is no preferred inertial frame?

A) Rutherford experiment

B) Photoelectric experiment

C) Michelson-Morley experiment

D) Young’s double slit experiment

22 / 30

According to special relativity, an observer moving with a light beam would:

A) See light moving backward

B) Measure light speed as zero

C) Measure light speed as $\mathbf{(c)}$

D) Stop time completely

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The first postulate applies specifically to:

A) Only stationary objects

B) All inertial frames

C) Only gravitational fields

D) All accelerating frames

24 / 30

Which statement is incorrect according to special relativity?

A) Speed of light is constant in vacuum.

B) Time is absolute for all observers.

C) Laws of physics are identical in inertial frames.

D) All inertial frames are equivalent.

25 / 30

Einstein’s postulates changed physics by showing that:

A) Light has no energy.

B) Motion does not affect measurements.

C) Newtonian mechanics is valid at all speeds.

D) Space and time are not absolute.

26 / 30

If an observer measures the speed of light from a moving source, the result will be:

A) Zero

B) $\mathbf{c}$ minus source speed

C) $\mathbf{c}$

D) $\mathbf{c}$ plus source speed

27 / 30

The special theory of relativity does not directly deal with:

A) Constant velocity motion

B) Inertial reference frames

C) Accelerating reference frames

D) Speed close to light

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Einstein’s postulates require that the value of $\mathbf{(c)}$ must be:

A) Zero in moving frames

B) Different for every observer

C) Dependent on mass

D) Constant in all inertial frames

29 / 30

The first and second postulates together lead to:

A) Elimination of energy

B) Constant acceleration of objects

C) Relativistic effects

D) Absolute space and time

30 / 30

The fundamental purpose of Einstein’s postulates was to:

A) Explain only gravitational effects

B) Remove the concept of velocity

C) Modify classical ideas to explain high-speed motion

D) Prove Newton’s laws are useless

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