Electrostatics MCQs

Question 1

Mobile phones often lose signal inside lifts because:

Accepted Answer

the metal lift acts as a Faraday cage

Answer

lifts have no air

Answer

the phone's battery drains

Answer

lifts are too high

Question 2

N/C is equivalent to:

Accepted Answer

V/m

Answer

W/A

Answer

C/m

Answer

J/C

Question 3

The electric field inside a charged hollow conducting sphere is:

Accepted Answer

zero

Answer

directed outward

Answer

the same as at the surface

Answer

infinite

Question 4

If the distance from a point charge is tripled, the field strength becomes:

Accepted Answer

one ninth

Answer

nine times

Answer

one third

Answer

three times

Question 5

An electric field is a region in which:

Accepted Answer

a charge experiences a force

Answer

no force acts

Answer

a magnet always experiences a force

Answer

a mass experiences a force

Question 6

For a mesh to act as a Faraday cage for waves, the holes must be:

Accepted Answer

much smaller than the wavelength

Answer

equal to the wavelength

Answer

any size

Answer

much larger than the wavelength

Question 7

An electron is between parallel plates 1 cm apart with 500 V across them. Its acceleration is (e = 1.6 10^-19 C, me = 9.11 10^-31 kg):

Accepted Answer

8.78 10^15 m/s^2

Answer

8.78 10^14 m/s^2

Answer

4.78 10^12 m/s^2

Answer

8.78 10^16 m/s^2

Question 8

In Coulomb's law, k =

Accepted Answer

14pivarepsilon0

Answer

1varepsilon0

Answer

varepsilon04pi

Answer

4pivarepsilon0

Question 9

The number of field lines leaving a charge is proportional to:

Accepted Answer

the size of the charge

Answer

the distance from it

Answer

the mass of the charge

Answer

its speed

Question 10

The field lines between two charged parallel plates are:

Accepted Answer

parallel and equally spaced

Answer

radial

Answer

circular

Answer

curved and crossing

Question 11

Sensitive electronic equipment is placed in metal boxes to:

Accepted Answer

shield it from external electric fields and interference

Answer

keep it warm

Answer

increase its current

Answer

make it heavier

Question 12

A charged balloon attracts small bits of paper because:

Accepted Answer

its electric field exerts forces on charges in the paper

Answer

of magnetism

Answer

of gravity

Answer

of air pressure

Question 13

The metal mesh in a microwave oven door:

Accepted Answer

keeps microwaves inside while letting visible light through

Answer

heats the food

Answer

reflects light

Answer

lets microwaves out

Question 14

A charge of 1.6 10^-19 C experiences a force of 6 10^-15 N. The electric field strength is:

Accepted Answer

37,500 N/C

Answer

3750 N/C

Answer

75,000 N/C

Answer

3.75 10^5 N/C

Question 15

Two parallel plates 2 cm apart have a p.d. of 200 V between them. The field strength between them is:

Accepted Answer

10,000 V/m

Answer

100 V/m

Answer

1000 V/m

Answer

1 10^5 V/m

Question 16

Distances for the field outside a charged sphere are measured from:

Accepted Answer

the centre of the sphere

Answer

the surface of the sphere

Answer

the nearest edge

Answer

infinity

Question 17

A metal sphere of radius 0.1 m carries 5 10^-9 C. The field strength 0.2 m from its centre is (k = 8.99 10^9 N m^2 C^-2):

Accepted Answer

1120 N/C

Answer

562 N/C

Answer

2250 N/C

Answer

4490 N/C

Question 18

The electric field strength 0.1 m from a point charge of 1 10^-9 C in free space is:

Accepted Answer

899 N/C

Answer

449 N/C

Answer

89.9 N/C

Answer

1800 N/C

Question 19

The deflection of a charged particle passing between plates increases if:

Accepted Answer

the p.d. between the plates is increased

Answer

the plates are made shorter

Answer

the plates are moved further apart

Answer

the particle moves faster

Question 20

The point-charge approximation for a sphere is valid:

Accepted Answer

only for points outside (or on) the sphere

Answer

only inside the sphere

Answer

everywhere including inside

Answer

never

Question 21

The value of varepsilon0 is about:

Accepted Answer

8.85 10^-12 F/m

Answer

6.67 10^-11 F/m

Answer

8.99 10^9 F/m

Answer

1.6 10^-19 F/m

Question 22

A difference between electric and gravitational fields is that electric forces:

Accepted Answer

can be attractive or repulsive

Answer

act only on masses

Answer

are much weaker

Answer

are always attractive

Question 23

The field 0.5 m from a point charge is 3.6 10^5 N/C. The charge is:

Accepted Answer

1 10^-5 C

Answer

5.01 10^-6 C

Answer

1 10^-4 C

Answer

2 10^-5 C

Question 24

An electric field is an example of a:

Accepted Answer

field of force

Answer

temperature field

Answer

sound field

Answer

scalar field only

Question 25

Coulomb's law states that the force between two point charges is:

Accepted Answer

proportional to the product of the charges and inversely proportional to the square of their separation

Answer

proportional to the separation

Answer

proportional to the sum of the charges

Answer

independent of distance

Electrostatics MCQs — Physics (page 4)

76. Mobile phones often lose signal inside lifts because:

77. N/C is equivalent to:

78. The electric field inside a charged hollow conducting sphere is:

79. If the distance from a point charge is tripled, the field strength becomes:

80. An electric field is a region in which:

81. For a mesh to act as a Faraday cage for waves, the holes must be:

82. An electron is between parallel plates 1 cm apart with 500 V across them. Its acceleration is (e = 1.6 10^-19 C, me = 9.11 10^-31 kg):

83. In Coulomb's law, k =

84. The number of field lines leaving a charge is proportional to:

85. The field lines between two charged parallel plates are:

86. Sensitive electronic equipment is placed in metal boxes to:

87. A charged balloon attracts small bits of paper because:

88. The metal mesh in a microwave oven door:

89. A charge of 1.6 10^-19 C experiences a force of 6 10^-15 N. The electric field strength is:

90. Two parallel plates 2 cm apart have a p.d. of 200 V between them. The field strength between them is:

91. Distances for the field outside a charged sphere are measured from:

92. A metal sphere of radius 0.1 m carries 5 10^-9 C. The field strength 0.2 m from its centre is (k = 8.99 10^9 N m^2 C^-2):

93. The electric field strength 0.1 m from a point charge of 1 10^-9 C in free space is:

94. The deflection of a charged particle passing between plates increases if:

95. The point-charge approximation for a sphere is valid:

96. The value of varepsilon0 is about:

97. A difference between electric and gravitational fields is that electric forces:

98. The field 0.5 m from a point charge is 3.6 10^5 N/C. The charge is:

99. An electric field is an example of a:

100. Coulomb's law states that the force between two point charges is:

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