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- Question
Pieces of camphor placed on water move about rapidly. This is because of
Options- A. diffusion
- B. viscosity
- C. surface tension
- D. capillarity
- Correct Answer
- surface tension
ExplanationThe Camphor slowly dissolves in the water lowering the latter's surface tension in the immediate neighbourhood. The stronger pull exerted by the uncontaminated portion of water brings about a movement of the surface and the camphor particles are carried along with it. When after sometime the whole surface settles for the reduced tension, the movement of the camphor too short.
- 1. The rate of change of linear momentum of a body falling freely under gravity is equal to it's ____ ?
Options- A. Kinetic Energy
- B. Weight
- C. Potential Energy
- D. Impulse Discuss
- 2. A bucket of water is hung from a spring balance. A piece of iron is suspended in the water without touching the sides or touching the bottom of the bucket. The reading of the spring balance
Options- A. will increase
- B. will decrease
- C. does not change
- D. varies with the increase of depth of the immersion of the iron piece Discuss
- 3. Masses of stars and galaxies are usually expressed in terms of
Options- A. neutron mass
- B. earth's mass
- C. solar mass
- D. lunar mass Discuss
- 4. Which is best used as a sound absorbing material in partition walls ?
Options- A. Stone chips
- B. Steel
- C. Glass - wool
- D. Glass pieces Discuss
- 5. To produce deflection in a television picture tube:
Options- A. an electric field is used
- B. a magnetic field is used
- C. both electric and magnetic field are used
- D. none of the above Discuss
- 6. When body is accelerated
Options- A. its velocity never changes
- B. its speed always changes
- C. its direction always changes
- D. its speed may or maynot change Discuss
- 7. In a freezer ice cubes will be formed more quickly in trays made of
Options- A. rubber
- B. plastic
- C. aluminium
- D. wood Discuss
- 8. Skating on ice is possible because
Options- A. the surface of ice is smooth
- B. ice is cold
- C. the pressure on the ice due to skate melts the ice by lowering its melting point forming a thin film of water
- D. the pressure on the ice due to skate raises its melting point Discuss
- 9. Mirage is an example of
Options- A. Reflection of light & Refraction of light
- B. Dispersion of light
- C. Total Internal Reflection
- D. Refraction of light & Total Internal Reflection of light Discuss
- 10. The base of an electric iron is brightly polished mainly
Options- A. to make it smooth and frictionless
- B. to make it rust-proof
- C. to reduce heat loss by radiation
- D. to make it more durable Discuss
Physics problems
Search Results
Correct Answer: Weight
Explanation:
Rate of change of impulse equals the force . In case of freely falling body the only force is the weight.
Correct Answer: will increase
Explanation:
When the piece of iron is lowered into the water, the water level in the bucket increases. And so the pressure at the bottom of bucket also increases. Thus the total thrust at the botto also increases. Therefore the spring balance reading increases.
Correct Answer: solar mass
Correct Answer: Glass - wool
Explanation:
Materials that do not transfer mechanical energy well. These tend to be soft,flexible, low density, and with high surface area to linear area ratios.
Correct Answer: a magnetic field is used
Correct Answer: its speed may or maynot change
Correct Answer: aluminium
Explanation:
Aluminium being a good conductor of heat conducts away the heat from the substance quite easily and causes quick freezing.
Correct Answer: the pressure on the ice due to skate melts the ice by lowering its melting point forming a thin film of water
Explanation:
Here is a case of lowering of melting point of ice with increase of pressure
Correct Answer: Refraction of light & Total Internal Reflection of light
Correct Answer: to reduce heat loss by radiation
Explanation:
Polished surfaces are poor radiators of heat. So loss of heat on that account is reduced and the electric iron remains hotter than otherwise.
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