Physics Exam

46. A person of mass 75 kg experiences a net force of 400 N when placed in an upward accelerating lift. What is its apparent weight?

A. 750 N
B. 400 N
C. 1150 N
D. 350 N

47. A block of mass 20 kg is pushed horizontally, at constant speed, along a rough horizontal floor over a distance of 5 m. If coefficient of kinetic friction between the block and the surface is 0.4, what is the amount of work done by friction?

A. -400 J
B. -100 J
C. -40 J
D. -1000 J

48. The velocity-time graph of an object moving along a straight line toward east is described by the figure shown below.

What is the total displacement moved by the object?

A. 600 m East
B. 525 m East
C. 375 m East
D. 450 m East

49. A 200 N force is required to be applied at one end of a 1 m long lever, 80 cm from its fulcrum, in order to lift a load of 600 N placed at the other end as shown in the figure below.

What is the efficiency of the lever?

A. 25%
B. 17%
C. 75%
D. 83%

50. A substance with a mass of 2 kg has a volume of 2.5×10⁻³ m³. What is the relative density of the substance?

A. 80
B. 8.0
C. 0.8
D. 1.25

51. Lenz's law states that the direction of the induced current in a loop is in such a way that the current

A. creates a magnetic field that opposes the change in magnetic flux through the loop.
B. is in the same direction as that of the applied magnetic field that is causing it.
C. creates a magnetic field that reinforces the change in magnetic flux through the loop.
D. is in opposite direction to that of the applied magnetic field that is causing it.

52. Which one of the following statements is correct about the resistance of a conducting wire? The resistance of the wire is

A. inversely proportional to its length.
B. inversely proportional to its cross-sectional area.
C. directly proportional to the square of its cross-sectional area.
D. directly proportional to the square of its length.

53. Consider an ideal transformer having Nₚ and Nₛ turns, and voltages Vₚ and Vₛ in its primary and secondary coils, respectively. Which one of the following is the correct ideal transformer equation?

A. Vₛ/Vₚ = Nₛ/Nₚ
B. Nₛ/Nₚ = (Vₛ/Vₚ)²
C. Vₚ/Vₛ = Nₚ/Nₛ
D. Vₚ = (Nₚ/Nₛ)² Vₛ

54. Which one of the following statements is correct about the electrical conductivity of materials?

A. Materials in which all the inner and outer most shell electrons are free to move within the material are conductors.
B. Materials in which all the inner and outer most shell electrons are tightly bound to its parent atom are insulators.
C. Materials in which all the outer most shell electrons are tightly bound to its parent atom are conductors.
D. Materials in which all the outer most shell electrons are free to move within the material are semiconductors.

55. Which of the following statements about the nature electromagnetic waves is correct? Electromagnetic waves are transverse waves produced when

A. electric and magnetic fields are oscillating parallel to each other.
B. charges are placed at rest in an electric and magnetic fields that are parallel to each other.
C. electric and magnetic fields are oscillating perpendicular to each other.
D. charges are placed at rest in an electric and magnetic fields that are perpendicular to each other.

56. Which one of the following statements distinguishes precision from accuracy?

A. Precision is a measure of the closeness of repeatedly measured values to each other, whereas accuracy is related to the number of significant figures.
B. Precision is a measure of the closeness of repeatedly measured values to each other, whereas accuracy refers to the closeness of measured values to the true value.
C. Precision indicates how close a measured value is to the true value, whereas accuracy refers to the closeness of repeatedly measured values to each other.
D. Accuracy measures how exact a value is whereas precision indicates how close a measured value is to the true value.

57. Three resistors are connected between points a and b as shown in the figure below.

The effective resistance of the circuit is

A. 1.0 kΩ
B. 11.0 kΩ
C. 1.0 Ω
D. 11.0 Ω

58. In an experiment to determine the direction of the magnetic field around a long straight current-carrying wire, a student placed a small compass at point P, as shown in the diagram.

If the direction of the current in the wire is directed out-of the page, then the magnetic needle of the compass will point

A. to the left
B. upward
C. to the right
D. downward

59. A concave mirror has a radius of curvature of 30.0 cm. It is positioned so that the upright image of an object is 2.0 times the size of the object. How far is the object from the mirror?

A. 22.5 cm
B. 7.5 cm
C. 10.0 cm
D. 15.0 cm

60. A combination of logic gate is constructed from an NAND gate and an OR gate, as shown in the diagram below.

The truth table for the logic circuit shown above is

A.

P	Q	Output
0	0	1
0	1	1
1	0	1
1	1	1

B.

P	Q	Output
0	0	1
0	1	0
1	0	0
1	1	1

C.

P	Q	Output
0	0	0
0	1	1
1	0	1
1	1	0

D.

P	Q	Output
0	0	0
0	1	0
1	0	0
1	1	0

Physics Exam: Part 4

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