Physics Practice Question and Answer
8 Q: Which of the following produces more flame?
1170 16137474b576b113a3f9cd690
6137474b576b113a3f9cd690- 1Steamtrue
- 2hot airfalse
- 3Sun raysfalse
- 4All thesefalse
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Answer : 1. "Steam"
Q: What is the color that is used in danger signals?
1169 05fe46a3d57a5647868b6522c
5fe46a3d57a5647868b6522c- 1Yellow colorfalse
- 2Purple colorfalse
- 3Blue colorfalse
- 4Red colortrue
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Answer : 4. "Red color"
Q: A 1 kg object is dropped from a height of 30 meters to the ground. The work done by the force of gravity will be
1167 05f86a39bb7ad805e26c16cb0
5f86a39bb7ad805e26c16cb0- 130 Jfalse
- 210 Jfalse
- 30.33 Jfalse
- 4300 Jtrue
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Answer : 4. "300 J"
Q: Creates a smaller image than the object?
1166 05f6da3be5256e8407c2e4412
5f6da3be5256e8407c2e4412- 1convex mirrorfalse
- 2concave mirrorfalse
- 3plane mirrorfalse
- 4Convex mirror and concave mirrortrue
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Answer : 4. "Convex mirror and concave mirror"
Q: How is 'Power’ interpreted?
1164 05f869be0b7ad805e26c0af01
5f869be0b7ad805e26c0af01- 1Work done in energy transferfalse
- 2Working rate or energy transfer ratetrue
- 3Work done in a minutefalse
- 4Force applied to increase the loadfalse
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Answer : 2. "Working rate or energy transfer rate "
Q: Which point in the human eye is not very sensitive to light, is it called?
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5fe42412eee69a704db5d664- 1Yellow Pointfalse
- 2blind pointtrue
- 3near pointfalse
- 4focal pointfalse
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Answer : 2. "blind point"
Q: Refraction of light is responsible for:
1155 06189e5479236c01fbea82faa
6189e5479236c01fbea82faa- 1Shadow formationfalse
- 2Twinkling of starstrue
- 3Blue color of the skyfalse
- 4Rainbowfalse
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Answer : 2. "Twinkling of stars"
Q: The coefficient performance of a refrigerator is 5. If the temperature inside the freezer is -20℃, calculate the heat rejected to the surrounding
1151 063c921551e8e3f3e1a3a5a0a
63c921551e8e3f3e1a3a5a0a- 1110Ctrue
- 2false
410C
- 3false
210C
- 4false
310C
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Answer : 1. "110C"
Explanation :
A heat pump is a heat engine working in reverse direction. A refrigerator is basically a heat pump, which is used to pump heat (absorbed from materials at lower temperatures inside the refrigerator) to the surroundings at higher temperatures. The coefficient of performance of a refrigerator is defined as the ratio of heat removed
Why
2
Energy from inside the refrigerator per cycle
w
given per cycle for heat removal,
α
,
Why
2
,
w
,