Explanation

The speed of light is much faster than the speed of sound in air.

Light travels 186 thousand miles in 1 second, while sound takes almost 5 seconds to travel 1 mile

Light is a electromagnetic wave that's why it travel faster than sound wave however electromagnetic waves don't need medium to travel but sound wave need medium to travel

ND5-07-2023

Explanation

The hepatitis A virus (HAV) is transmitted through ingestion of contaminated food and water or through direct contact with an infectious person. 

MUG 11-12-2022

Explanation

• The Candela (cd) is the SI unit of luminous intensity.
• It is defined as the luminous intensity of a monochromatic source that emits light at a frequency of 540 x 10^12 Hz with a luminous efficiency of 683 lm/W.

Explanation

Explanation

Calorie is a larger unit of energy.

1 Calorie ≈ 4.184 Joules.

1 Joule = 10⁷ Ergs.

1 Electron Volt (eV) = 1.602 × 10⁻¹⁹ Joules.

Calorie is commonly used to measure energy in food and metabolic processes.

Explanation

The weight of a man in an elevator descending with an acceleration of 4.9 m/s² will become:

Let:

• Actual weight $W=mg$

• Acceleration due to gravity g=9.8m/s^2

• Acceleration of the elevator a=4.9m/s^2

When an elevator descends with acceleration $a$, the apparent weight becomes:

W′=m(g−a)

Substitute values:

W′=m(9.8−4.9)=m(4.9)
W′=1​/2×mg

So, the apparent weight becomes half of the actual weight.

Explanation

As ice cream melts, it absorbs thermal energy from the surroundings, but its internal thermal energy decreases as it changes from solid to liquid.

This is a physical change.

Explanation

Explanation

Explanation