PH | MCQs

Explanation

take it out

اسے باہر لے

“Take it out “

Passive voice would be

Let it be taken out.

Explanation

The idiom "tooth and nails" means:  پوری طاقت سے، دل و جان سے آخر تک مقابلہ کرنا

Explanation

Philately is the hobby of collecting and studying postage stamps.

It involves collecting, categorizing, and analyzing stamps from around the world.

As well as learning about their history, design, and production.

Explanation

hot is burn

similarly cold is to freeze

Explanation

Weight is a vector quantity because it has both magnitude (amount of force) and direction (downward, towards the center of the Earth).

Explanation

Mercury is the only elemental metal that remains in a liquid state at room temperature (around 25°C).

It is used in thermometers, barometers, and other scientific instruments due to this unique property.

Four other elements are liquids slightly warmer than room temperature.

They are:

1. Francium
2. Cesium
3. Gallium
4. Rubidium

Explanation

The speed of sound in steel at 20°C is approximately 5100–5200 m/s, with 5130 m/s being a widely accepted value.

Sound travels faster in solids like steel due to their high density and elasticity compared to gases and liquids.

Explanation

Muscle is a type of tissue that contracts to produce movement.

The three main types of muscle tissues are skeletal, smooth, and cardiac.

Explanation

Explanation

To find the self-inductance of a coil, we can use the formula:

L = (ΔΦ / ΔI)

Where:

L is the self-inductance in Henry (H),

ΔΦ is the change in magnetic flux in Weber (Wb),

and ΔI is the change in current in Ampere (A).

In this case, the current changes from 5A to 0A (nil) in 5 seconds. (ΔI) is therefore 5A - 0A = 5A.

To find the change in (ΔΦ), we can use Faraday's law of electromagnetic induction

ΔΦ = L * ΔI

Since the current changes from 5A to 0A in 5 seconds, the rate of  (ΔI) is 5A / 5s = 1A/s.

Substituting the values into the equation:

ΔΦ = L * ΔI

500 V = L * 1 A/s

Since the (V) is equal to  (L) and  (ΔI), we can rewrite the equation as:

L = 500 V / 1 A/s

Simplifying the equation gives us:

L = 500 H

Therefore, the self-inductance of the coil is 500 Henry (H).