1. According to Einstein's mass-energy equivalence principle, the energy equivalent of a mass m is given by
A.
E = mc
B.
E = mc²
C.
E = m/c²
D.
E = m²c
Correct Answer:
E = mc²
Explanation:
Einstein's mass-energy equivalence relation is E = mc², where E is energy, m is mass, and c is the speed of light in vacuum.
2. The value of the speed of light used in the mass-energy equivalence relation is approximately
A.
3 × 10⁶ m/s
B.
3 × 10⁷ m/s
C.
3 × 10⁸ m/s
D.
3 × 10⁹ m/s
Correct Answer:
3 × 10⁸ m/s
Explanation:
The speed of light in vacuum is approximately 3 × 10⁸ m/s, and this value is used in E = mc².
3. If the mass of an object increases, its equivalent energy according to E = mc²
A.
decreases
B.
remains zero
C.
remains unchanged
D.
increases
Correct Answer:
increases
Explanation:
Since E = mc² and c² is constant, equivalent energy increases directly with mass.
4. The energy equivalent of 1 atomic mass unit (u) is approximately
A.
9.315 MeV
B.
93.15 MeV
C.
931.5 MeV
D.
9315 MeV
Correct Answer:
931.5 MeV
Explanation:
Using E = mc², the energy equivalent of 1 u is approximately 931.5 MeV.
5. If a mass of 2 kg is completely converted into energy, the energy produced is calculated using
A.
E = 2c²
B.
E = c²/2
C.
E = 2/c²
D.
E = c/2
Correct Answer:
E = 2c²
Explanation:
Substituting m = 2 kg into E = mc² gives E = 2c² joules.
6. The SI unit of energy obtained from the relation E = mc² is
A.
joule
B.
watt
C.
newton
D.
kilogram
Correct Answer:
joule
Explanation:
In SI units, mass is measured in kilograms and speed in metres per second, so mc² has the unit kg m²/s², which is a joule.
7. A very small loss of mass in a nuclear process can produce a large amount of energy because
A.
the speed of light is very small
B.
the speed of light is squared in E = mc²
C.
mass is always zero in nuclear processes
D.
energy is independent of mass
Correct Answer:
the speed of light is squared in E = mc²
Explanation:
The factor c² is extremely large, so even a small mass change corresponds to a large amount of energy.
8. If the mass converted into energy is doubled, the equivalent energy becomes
A.
half
B.
one-fourth
C.
double
D.
four times
Correct Answer:
double
Explanation:
From E = mc², energy is directly proportional to mass. Therefore, doubling the mass doubles the equivalent energy.
9. The energy equivalent of a mass defect of 0.01 u is approximately
A.
0.09315 MeV
B.
0.9315 MeV
C.
9.315 MeV
D.
93.15 MeV
Correct Answer:
9.315 MeV
Explanation:
Since 1 u corresponds to 931.5 MeV, 0.01 u corresponds to 0.01 × 931.5 = 9.315 MeV.
10. Mass-energy equivalence means that mass can be regarded as
A.
a form of energy
B.
a form of force only
C.
unrelated to energy
D.
a unit of power
Correct Answer:
a form of energy
Explanation:
The relation E = mc² shows that mass possesses an equivalent amount of energy and can be converted into energy.
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