Physics Practice Question and Answer
8 Q: The coefficient performance of a refrigerator is 5. If the temperature inside the freezer is -20℃, calculate the heat rejected to the surrounding
1219 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
,
Q: How is 'Power’ interpreted?
1216 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: The measure of inductance is
1206 161655ebe3d260361529b137f
61655ebe3d260361529b137f- 1Henrytrue
- 2Ohmfalse
- 3Amperefalse
- 4Coulombfalse
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Answer : 1. "Henry "
Q: Can eyes with vision be seen clearly?
1204 05fe423abeee69a704db5d457
5fe423abeee69a704db5d457- 1Nearby objectsfalse
- 2Big itemsfalse
- 3distant objectstrue
- 4None of thesefalse
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Answer : 3. "distant objects"
Q: When resistors are connected in series, then net resistance____.
1202 26099137c1c52c418ae4c60eb
6099137c1c52c418ae4c60eb- 1Increasestrue
- 2Decreasesfalse
- 3Remains samefalse
- 4None of thesefalse
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Answer : 1. "Increases "
Q: In the human eye?
1194 05fe4599257a5647868b5e752
5fe4599257a5647868b5e752- 1In the human eye?false
- 2convex mirrorfalse
- 3convex lenstrue
- 4concave mirrorfalse
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Answer : 3. "convex lens"
Q: A potentiometer is considered a versatile and accurate device to make an electrical measurement of EMF. Why?
1193 063c8d7f2bdbddb32fda0219d
63c8d7f2bdbddb32fda0219d- 1Because the method involves a combinationfalse
- 2There are cells involvedfalse
- 3Because of potential gradientsfalse
- 4As there is no flow of current through the galvanometertrue
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Answer : 4. "As there is no flow of current through the galvanometer"
Explanation :
A potentiometer is an accurate and versatile device to make electrical measurements of emf because the method involves a condition of no current flow through the galvanometer, the device can be used to measure potential difference, internal resistance of a cell and compare emf's of two sources. Q.
Q: Who gave the theory of gravity?
1193 061655b5c3d260361529b0876
61655b5c3d260361529b0876- 1Isaac Newtontrue
- 2John Adamsfalse
- 3Charles Newtonfalse
- 4Charles Babbagefalse
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