UPSC  Physics

71. What is the increasing order of the wavelengths of the following colours?
1. Orange
2. Indigo
3. Yellow
4. Violet

1, 2, 3 and 4 3, 1, 4 and 2 1, 3, 2 and 4 4, 2, 3 and 1

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72. A ball is dropped from the top of a high building with a constant acceleration of 9.8 m/s2. What will be its velocity after 2 seconds?

9.8 m/s 19.6 m/s 29.4 m/s 39.2 m/s

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73. A hunter aims his gun at a point between the eyebrows of a monkey sitting on a branch of a tree. Just as he fires, the monkey jumps down. The bullet will:

hit the monkey at the point aimed hit the monkey below the point aimed hit he monkey above the point aimed miss the monkey altogether

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74. Consider the following features of newer models of motor cars:
1. Radial tyres
2. Streamlined body
3. Multipoint fuel injection
4. Catalytic converter with exhaust
Which of these features make the new models of motor cars more fuel efficient?

1 and 2 2 and 3 2, 3 and 4 1, 3 and 4

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75. Assertion (A): A man standing on a completely frictionless surface can propel himself by whistling.
Reason (R): If no external force acts on a system, its momentum cannot change.
Codes:

Both A and R are true and R is the correct explanation of A Both A and R are true but R is not a correct explanation of A A is true but R is false A is false but R is true

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76. Consider the following statements: A simple pendulum is set into oscillation. Then:
1. the acceleration is zero when the bob passes through the mean position.
2. in each cycle the bob attains a given velocity twice.
3. both acceleration and velocity of the bob are zero
when it reaches its extreme position during the oscillation.
4. the amplitude of oscillation of the simple pendulum decreases with time.
Which of these statements are correct?

1 and 2 3 and 4 1, 2 and 4 2, 3 and 4

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77. Assertion (A): With the increase of temperature, the viscosity of glycerine increases.
Reason (R): Rise of temperature increases kinetic energy of molecules.
Codes:

Both A and R are true and R is the correct explanation of A Both A and R are true but R is not a correct explanation of A A is true but R is false A is false but R is true

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78. Assertion (A): An iron ball floats on mercury but gets immersed in water.
Reason (R): The specific gravity of iron is more than that of mercury.
Codes:

Both A and R are true and R is the correct explanation of A Both A and R are true but R is not a correct explanation of A A is true but R is false A is false but R is true

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79. Consider the following statements:
A 4-wheel vehicle moving in a sharp circular path at high speed will:
1. overturn about its outer wheels
2. overturn about its inner wheels
3. skid outwards
4. skid inwards
Which of these statements are correct?

1 and 3 2 and 4 2 and 3 1 and 4

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80. An oil tanker partially filled with oil moves forward on a level road with uniform acceleration. The free surface of oil then:

remains horizontal is inclined to the horizontal with smaller depth at the rear end is inclined to the horizontal with larger depth at the rear end assumes a parabolic curve

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