Explanation

Reverberation time is mainly influenced by:

• The volume of the room

• The absorptive properties of surfaces

• The number of sound-absorbing objects or people

While absorption can vary slightly with frequency, the frequency itself is not a primary controlling factor of reverberation time.

Explanation

Helium hydride (HeH+) was the first molecule discovered in space, identified in 2019 by astronomers.

It was found in a planetary nebula, marking a significant discovery in molecular chemistry in space.

Explanation

Mercury remains liquid at a wide range of temperatures, has uniform expansion.

It is easily visible due to its opacity.

It does not stick to glass, allowing accurate and consistent readings in thermometers.

Explanation

Let's denote the weight of the man in the stationary lift as W and the weight in the accelerating lift as W'.

We know that W' / W = 2/3.

When the lift is accelerating downward with acceleration 'a', the apparent weight (W') is given by:

W' = W - ma

where m is the mass of the man.

Since W' / W = 2/3, we can write:

(W - ma) / W = 2/3

Substitute W = mg (where g is the acceleration due to gravity):

(mg - ma) / mg = 2/3

Simplify:

g - a = (2/3)g

a = g - (2/3)g

a = (1/3)g

a = g/3

Explanation

Explanation

Explanation

In a DC (direct current) circuit, the most fundamental and commonly referenced basic circuit element is the resistor.

Here's why:

Resistor: In a DC circuit, a resistor is used to control the current and voltage levels.

It provides a specific amount of resistance, which determines how much current will flow for a given voltage according to Ohm's Law (𝑉 = 𝐼/𝑅).

Explanation

Sirius is the brightest star in the night sky.

Sirius means صبح کا ستارہ 

Explanation

The triple point of water is the unique temperature and pressure at which water coexists in all three phases — solid, liquid, and gas — in equilibrium.

Temperature: 273.16 Kelvin

This is used as a fundamental fixed point in defining the Kelvin temperature scale.

Explanation

Rocket velocity is governed by the rocket equation, which depends on exhaust velocity and the rate of mass ejection.

Higher exhaust velocity and more mass loss (fuel ejection) produce greater thrust, resulting in higher rocket velocity.