Physics Questions Practice Question and Answer
8 Q: A potentiometer is considered a versatile and accurate device to make an electrical measurement of EMF. Why?
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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: Used in solar cooker?
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5f6da8ddec13dd74800548f7- 1concave mirrortrue
- 2convex mirrorfalse
- 3plane mirrorfalse
- 4None of thesefalse
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Answer : 1. "concave mirror"
Q: What constitutes current in a metal wire.
1647 05f571942df171125cbc17f3c
5f571942df171125cbc17f3c- 1neutronsfalse
- 2protonsfalse
- 3electronstrue
- 4None of thesefalse
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Answer : 3. "electrons"
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
1646 05f86a39bb7ad805e26c16cb0
5f86a39bb7ad805e26c16cb0- 130 Jfalse
- 210 Jfalse
- 30.33 Jfalse
- 4300 Jtrue
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Answer : 4. "300 J"
Q: Sun appears when rising and setting?
1633 05fe459e157a5647868b5ea39
5fe459e157a5647868b5ea39- 1Redtrue
- 2Bluefalse
- 3Blackfalse
- 4Yellowfalse
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Answer : 1. "Red"
Q: Who gave the theory of gravity?
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61655b5c3d260361529b0876- 1Isaac Newtontrue
- 2John Adamsfalse
- 3Charles Newtonfalse
- 4Charles Babbagefalse
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Answer : 1. "Isaac Newton "
Q: The unit of which physical quantity is not pascal?
1631 0605c55f33af5ff63fd6b4361
605c55f33af5ff63fd6b4361- 1Moment of inertiatrue
- 2Pressurefalse
- 3Stressfalse
- 4Young’s modulusfalse
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Answer : 1. "Moment of inertia"
Q: The coefficient performance of a refrigerator is 5. If the temperature inside the freezer is -20℃, calculate the heat rejected to the surrounding
1628 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
,