Q. What is the main characteristic of a black hole according to general relativity?
A.
It has infinite density and zero volume.
B.
It emits light.
C.
It can be seen with the naked eye.
D.
It has a strong magnetic field.
Solution
According to general relativity, a black hole is a region of spacetime where gravity is so strong that nothing, not even light, can escape from it, leading to the concept of infinite density at its singularity.
Correct Answer:
A
— It has infinite density and zero volume.
Q. What is the principle behind Einstein's theory of special relativity?
A.
The speed of light is constant in all inertial frames of reference.
B.
Mass is always conserved in a closed system.
C.
Energy cannot be created or destroyed.
D.
Forces are equal and opposite.
Solution
Einstein's theory of special relativity is based on the postulate that the speed of light in a vacuum is constant and does not depend on the motion of the observer or the source of light.
Correct Answer:
A
— The speed of light is constant in all inertial frames of reference.
Q. What is the relativistic effect observed when an object approaches the speed of light?
A.
Time dilation
B.
Length contraction
C.
Mass increase
D.
All of the above
Solution
As an object approaches the speed of light, it experiences time dilation, length contraction, and an increase in relativistic mass, all predicted by Einstein's theory of relativity.
Q. What phenomenon explains the emission of electrons from a material when light shines on it?
A.
Photoelectric effect
B.
Compton scattering
C.
Quantum tunneling
D.
Thermal emission
Solution
The photoelectric effect is the phenomenon where electrons are emitted from a material when it is exposed to light of sufficient frequency, demonstrating the particle nature of light.
