Free Physics20 Practice Test - IAS 

Question 1

10. Which of the following statements about Magnetic Resonance Imaging is not true?

A. It is a medical imaging technique used in radiology to visualize internal structures of the body in detail
B. MRI makes use of the property of nuclear magnetic resonance (NMR) to image nuclei of atoms inside the body.
C. MRI uses ionizing radiation to produce detailed analysis of the body
D. MRI machines make use of the fact that body tissue contains lots of water, and hence protons which get aligned in a large magnetic field

SOLUTION

Solution : C

Option:(c)

Question 2

9. Which of the following is not one of the laws of thermodynamics?

A. 1. The increase in internal energy of a closed system is equal to the difference of the heat supplied to the system and the work done by it
B. 2. Heat cannot spontaneously flow from a colder location to a hotter location
C. As a system approaches absolute zero the entropy of the system approaches a minimum value
D. A perpetual motion machine can be designed by gradually lowering a system from higher temperature to lower temperature

SOLUTION

Solution : D

Option:(4)

Question 3

A liquid is flowing in a streamlined manner through a cylindrical pipe. Along a section containing the axis of the pipe, the flow profile will be

A.
B.
C.
D.

SOLUTION

Solution : A

Option:(a)

Question 4

Which of the following is the correct sequence of the regions of the sun as one moves from its core to the surface?
1.Photosphere
2.Chromosphere
3.Convection zone
4.Corona

A. 1, 2, 3, 4
B. 1, 3, 4, 2
C. 2, 3, 4, 1
D. 2, 1, 3, 4

SOLUTION

Solution : A

Option:(a)

Question 5

The surface of water in a pond remains cool even on a hot day because

A. water evaporates at the surface and evaporation causes cooling
B. the heat absorbed at the surface is transmitted downwards
C. water in a contact with the bottom of the pond becomes cool and rises to the surface due to convention
D. none of these

SOLUTION

Solution : A

Option:(a)

Question 6

One feels cold after a dip in sea water due to

A. convection currents
B. the deposition of salt on the body
C. the evaporation of water on the body
D. the difference in temperatures between land and sea

SOLUTION

Solution : C

Option:(c)

Question 7

Scalding with steam is more severe than scalding by boiling water because

A. steam can penetrate the skin
B. steam is at a higher temperature
C. steam contains more energy than boiling water
D. steam is at a higher pressure

SOLUTION

Solution : C

Option:(c)

Question 8

Perspiration is maximum when

A. temperature is high and air is dry
B. temperature is high and air is humid
C. temperature is low and air is humid
D. temperature is low and air is dry

SOLUTION

Solution : B

Option:(b)

Question 9

During summer, we feel comfortable under a fan because it

A. throws cool air on us
B. sets the air in motion, thereby increasing the evaporation of sweat
C. produces convection currents
D. produces air which carries heat away from the body

SOLUTION

Solution : B

Option:(b)

Question 10

Consider the following statements:
1.In a direct-to-home (DTH) system, the viewers' dish antenna picks up signals from the satellite directly.
2.Cable operators receive signal from the satellite on large community dish antennas and then transmit to viewers' sets.
Which of the above statements is/are correct?

A. Only 1
B. Only 2
C. Both 1 and 2
D. Neither 1 nor 2

SOLUTION

Solution : C

Option:(c)

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