Explanation

Pair production occurs when a high-energy γ-ray photon is converted into an electron and a positron near a nucleus.

It is a quantum phenomenon that requires photon energy greater than 1.022 MeV.

Explanation

Force is defined as the rate of change of linear momentum with respect to time.

According to Newton’s second law, force causes a change in an object’s momentum.

Explanation

Commutative property means the order doesn’t matter: 𝐴 ∗ 𝐵 = 𝐵 ∗ 𝐴.

Union ∪ is commutative, so 𝐴 ∪ 𝐵 = 𝐵 ∪ 𝐴.

Explanation

• When light enters from a vacuum into glass, its velocity decreases.
• This is because light travels at a speed of approximately 299,792,458 meters per second (m/s) in a vacuum, but it travels at a slower speed in a medium with a higher refractive index, such as glass.

Explanation

Gamma rays consist of radiations similar to x-rays.

They are high-energy electromagnetic waves with no mass or charge.

Explanation

• In March 1929, Muhammad Ali Jinnah presented his 14 Points during a Muslim League session in Delhi to protect Muslim rights and interests.
• He had left for England in May 1928.
• He had returned after six months.
• The Nehru Report of 1928 influenced these points, which were consolidated with help from Muhammad Ali Jauhar.
• Jinnah’s Fourteen Points (1929) aimed to safeguard Muslim rights in British India.

They included:

1. Federal constitution with provincial powers.
2. Provincial autonomy.
3. No constitutional changes without state agreement.
4. Adequate Muslim representation in legislatures.
5. Muslim representation in services and self-governing bodies.
6. 1/3rd Muslim representation in the Central Legislature.
7. 1/3rd Muslim members in central and state cabinets.
8. Separate electorates.
9. No bill passed if 3/4th of a minority opposes it.
10. Reorganisation should not affect Muslim majorities in Bengal, Punjab, and NWFP.
11. Separation of Sindh from Bombay Presidency.
12. Reforms in NWFP and Balochistan.
13. Full religious freedom.
14. Protection of Muslim religious, cultural, educational, and linguistic rights.

Explanation

A tangent is a line that touches a circle at exactly one point.

It does not cross the circle and is perpendicular to the radius at the point of contact.

Explanation

The kinetic energy (KE) of an electron in the nth orbit is given by:

KE = 1/2mv²n

Where m is the mass of the electron and vn is its velocity in the nth orbit.

Explanation

Spring potential energy is given by U = 1/2kx².

If stretching to distance S gives 10 J, then to stretch to 2S, the energy becomes 1/2k(2S)² = 4×10 = 40 J.

So, additional work =  40−10 = 30 J.

Explanation

"People" is plural, so the verb must be plural too.

"Were" is the past tense plural form of "to be," matching the sentence context.