Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice particles of a gas ideal gases physics

Sugar particles slowly dissolve in water. This shows

  1. Refractive properties of water

  2. Motion of molecules in a substance

  3. Motion of substance

  4. Magic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sugar mixes in water because of motion of sugar molecules around water molecules.Overall a diffusion process is seen in it as sugar particles diffuse into water particles.

Multiple choice particles of a gas ideal gases physics

Speed of molecules is _______ in hot water than in cold water

  1. more

  2. less

  3. equal

  4. less than or equal to
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As molecules are heated, they gain kinetic energy and hence speed.We already know that kinetic energy is proportional to temperature of random moving particles.

Multiple choice particles of a gas ideal gases physics

Smoke rising from chimneys is example of

  1. Thermionic radiation

  2. Heating of molecules in a substance

  3. Motion of molecules in a substance

  4. Heat radiation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Due to diffusion, smoke molecules leave the chimney and spreads in the atmosphere.Overall a diffusion process is seen in it as smoke particles diffuse into air particles.

Multiple choice particles of a gas ideal gases physics

Heating a liquid expands it because

  1. Molecules gain potential energy and due to it, motion of molecules is increased

  2. Molecules gain kinetic energy and due to it, motion of molecules is increased

  3. Molecules gain kinetic energy and due to it, motion of molecules is reduced

  4. Molecules gain potential energy and due to it, motion of molecules is reduced
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

As a liquid is heated, its molecules gain kinetic energy, motion of molecules is increased and the liquid expands.Overall interparticle distance increases.

Multiple choice particles of a gas ideal gases physics

In convection,

  1. Heat transfers by radiation of infrared waves

  2. Heat transfers by motion of molecules in a substance

  3. Heat transfers by collision of molecules

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In convection, heat transfer occurs because of motion of molecules of substance in upward direction.Convection, occurs due to temperature differences which affect the density, and thus relative buoyancy, of the fluid. Heavier (more dense) components will fall, while lighter (less dense) components rise, leading to bulk fluid movement.

Multiple choice particles of a gas ideal gases physics

Water is a universal solvent. During mixing,

  1. Molecules of the water are distributed uniformly across the solute.

  2. Molecules of the solute are distributed uniformly across the volume of water.

  3. Molecules of the solute and molecules of water both move very fast to make the solution.

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

As a solute is added to the water and mixed, its molecules are spread across the volume of water and solute is then dissolved in water.

Multiple choice particles of a gas ideal gases physics

Due to motion of molecules in a substance

  1. Smell of perfume spreads around the room

  2. Perfume bottle spreads around the room

  3. Perfume cools the room

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When perfume is sprayed in corner of a room, its molecules moves around the room due to diffusion spreading the fragrance. Overall a diffusion process is seen in it as perfume particles diffuse into air particles.

Multiple choice laws of heat transfer heat and thermodynamics physics

Which one of the following is the characteristic of Planck's quantum theory of radiation?

  1. The energy is not absorbed or emitted in integral multiple of quantum of energy.

  2. Radiation energy is not emitted or absorbed continuously but in the form of small packets of energy

  3. Radiation energy is emitted or absorbed continuously

  4. The magnitude of energy associated with a quantum is inversely proportional to its frequency
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to Planck's quantum theory, radiation is emitted in the form of small packets of energy and is not continuous. Quantum of energy can be expressed by the relation E=hv, where h is Planck's constant and v is the frequency.

Multiple choice laws of heat transfer heat and thermodynamics physics

Pervost's theory of heat exchange is not applicable at temperature

  1. $0^oR$

  2. $0^oC$

  3. $0 K$

  4. $0^oF$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Prevost postulated that  radiative equilibrium is the condition where a steady state system is in dynamic equilibrium, with equal incoming and outgoing radiative flux and negligible heat transfer by conduction and convection.
So by extended logic, at $0K$ equilibrium cannot be reached.