Explanation

• Increasing the number of slits in a diffraction grating increases intensity.
• More slits means more waves interfere constructively at the central maximum.
• This results in stronger and sharper central bright fringe.
• Energy is concentrated more effectively in the main maxima.

Last verified on 05-06-2026

Explanation

• Driven harmonic oscillator is a system undergoing forced vibration.
• In forced vibrations, an external periodic force continuously acts on the system.
• The system oscillates with the frequency of the applied force.
• This differs from free oscillations, where no external force acts.

Last verified on 05-06-2026

Explanation

• He–Ne laser is a four-level laser system.
• It uses a mixture of helium and neon gases as the active medium.
• Four-level lasers are more efficient because population inversion is easier to achieve.
• Ruby laser is a three-level laser.

Last verified on 05-06-2026

Explanation

• The body cannot return to its original position when stress exceeds the elastic limit.
• Beyond the maximum elastic value, the material undergoes permanent deformation.
• Even after removing the stress, the original shape is not fully recovered.
• This behavior is called plastic deformation.

Last verified on 05-06-2026

Explanation

• The semi-major axis and the time period are related by Kepler's Third Law (Law of Periods).
• It states that the square of a planet's orbital period is proportional to the cube of its semi-major axis.
• Larger orbits take longer to complete.
• This law helps determine planetary distances and orbital periods.

Last verified on 05-06-2026

Explanation

1. ∂/∂x (x + 3y) = 1  
2. ∂/∂y (y - 2z) = 1  
3. ∂/∂z (x + mz) = m  

Explanation

• "If you had followed the rules, you would not have been disqualified."
• This is a third conditional (unreal past condition).
• Structure: If + past perfect → would have + past participle.
• It talks about a past situation that did not happen.

Last verified on 05-06-2026

Explanation

• “Has been + verb(-ing)” shows an action that started in the past and continues to now (present perfect continuous).
• “For a year now” indicates duration up to the present.

Last verified on 05-06-2026

Explanation

• The correct fixed structure is “no point in + verb(-ing)”.
• “In arguing” shows the activity being useless.

Last verified on 05-06-2026

Explanation

• “Worried about” is the correct fixed prepositional phrase.
• It shows concern for something specific.

Last verified on 05-06-2026