Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics
Find the accurate expressions.

  1. $E = mc^2$

  2. $E = m/c^2$

  3. $M = Ec^2$

  4. All of the expressions are accurate.

  5. $c = Em^2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Before Sir Einstien, mass and energy were two completely different physical quantities, which were not related to each other anyway. Sir Einstein told that energy and mass are related to each other i.e. energy and mass can be converted into each other by the following relation:

      $E=mc^{2}$, called Sir Einstein's mass-energy equivalence

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics
Which of the following statement is accurate for an object approaching the speed of light ?

  1. The particle's mass will increase as it approaches the speed of light.

  2. The particle's mass will increase as it approaches, and then decrease when it reaches the speed of light.

  3. The particle's mass will decrease as it approaches the speed of light.

  4. The particle's dimensions will increase but it's mass will remain constant as it approaches the speed of light.

  5. All of the statements are accurate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The mass of object as observed by a moving observer is given by $m=\dfrac{m _0}{\sqrt{1-(\dfrac{v}{c})^2}}$.

where $m _0$ is the rest mass of the object.

Hence, as speed approaches the speed of light, that is, as $v\rightarrow c$, $m\rightarrow \infty$

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

The unit of rate constant for a zero order reaction is:

  1. $s^{-1}$

  2. $mol L^{-1}s^{-1}$

  3. $L mol ^{-1}s^{-1}$

  4. $L^{2} mol ^{-2}s^{-1}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
For zero order reaction
Rate $=K[A]^0$
Rate $=K=\cfrac{d[A]}{dt}$
Unit of rate constant $=Unit\; of \; \cfrac{d[A]}{dt} \\=\cfrac{mol L^{-1}}{sec} \\=mol L^{-1} sec^{-1}$
Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Which of the following assertions are correct?

  1. A neutron can decay to a proton only inside a nucleus

  2. A proton can change to a neutron only inside a nucleus

  3. An isolated neutron can change into proton

  4. An isolated proton can change into a neutron
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A free proton is stable. A proton inside a nucleus can change into a neutron via beta-plus decay or electron capture to reach a more stable state.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Inside nucleus, protons are held together though they have the dame charge. Why?

  1. The strong attractive nuclear force far exceeds the electrostatic force between the protons

  2. Neutrons prevent them from repelling from each other

  3. The electrostatic attractive force between an electron and a proton is more than the electrostatic repulsive force between the protons

  4. Gluons are responsible for holding them together
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Protons within a nucleus experience strong electrostatic repulsion due to their positive charges. The strong nuclear force, which is an attractive force acting between nucleons at very short ranges, is significantly stronger than this electrostatic repulsion, thereby holding the nucleus together.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

The conversion of 1 u of mass results in ________ eV of energy.

  1. <span>$9.315 \times 10^6$</span>

  2. <span>$391.5 \times 10^6$</span>

  3. <span>$931.5 \times 10^6$</span>

  4. <span>$93.15 \times 10^6$</span>
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

According to Einstein's mass-energy equivalence principle, 1 atomic mass unit (u) is equivalent to approximately 931.5 MeV of energy. Since 1 MeV equals 10^6 eV, 931.5 MeV equals 931.5 * 10^6 eV.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Magnitude of mass defect is a measure of ......................... of a nucleus.

  1. Unstability

  2. Stability

  3. Charge

  4. Position
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mass defect represents the difference between the mass of a nucleus and the sum of the masses of its individual nucleons. A larger mass defect corresponds to a higher binding energy per nucleon, which indicates greater nuclear stability.