Explanation

A hydrogen-filled balloon expands as it rises and may even burst after rising very high in the atmosphere

As one goes high, the weight of the atmosphere above decreases and so does the pressure.

Thus for a balloon filled on the ground, the pressure inside the balloon exceeds that outside and thus it bursts.

Explanation

The energy of the sun is the original source of most of the energy found on earth.

The principal source of energy: the Sun

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ND10-1-2023

Explanation

Sir Isaac Newton was an English mathematician, physicist, astronomer, alchemist, theologian,

Author widely recognised as one of the greatest mathematicians

And physicists of all time and among the most influential scientists. 

Explanation

In liquids, particles are quite close together and move with random motion throughout the container.

Particles move rapidly in all directions but collide with each other more frequently than gases due to shorter distances between particles.

With an increase in temperature, the particles move faster as they gain kinetic energy, resulting in increased collision rates and an increased rate of diffusion.

ND2-03-2023

Explanation

Ultrasound is sound with frequencies greater than 20 kilohertz.

This frequency is the approximate upper audible limit of human hearing in healthy young adults

while 

The first article on the history of ultrasound was written in 1948

Explanation

Copper has the highest thermal conductivity (386 K m-1 K-1)

Copper has high thermal conductivity.

AGM 25-12-2022

Explanation

Heat conduction is a process in which heat is transferred from the hotter part to the colder part in a body without involving any actual movement of the molecules of the body.

AGM 25-12-2022

Explanation

Conventionally, clockwise torque is taken as negative

because clocks run in a negative direction according to the right-hand rule.

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Counterclockwise is the positive rotation direction

Explanation

The phenomenon of refraction of light is the shift in the path of light as it travels from one medium to another

Explanation

A galvanometer is an instrument that can detect and measure small amounts of current in an electrical circuit