Deck 7: Electricity and Magnetism

Question 1

Mean drift velocity of electron in a copper wire having cross-sectional area 5.0 × 10 ^-6 m² carrying current of 1 A and having number density 8.5 × 10 ²⁸ m³ is {{}}

A)0.015 mm s^-1
B)0.1 mm s^-1
C)0.5 mm s^-1
D)0.25 mm s^-1

Answer 1

0.015 mm s^-1

Question 2

Magnitude of charge is known as

A)charge count
B)elementary charge
C)elementary count
D)charge number

Answer 2

elementary charge

Question 3

1 Ω is equal to

A)1 V A-2
B)1 V A^-1
C)1 V^-1 A
D)2 V A^-1

Answer 3

1 V A^-1

Question 4

To protect wiring from excessive passing of current is

A)voltmeter
B)fuse
C)galvanometer
D)resistance

Question 5

Current in a 60 W light bulb when it is connected to a 230 V power supply is

A)0.26 A
B)1.5 A
C)2.6 A
D)3.9 A

Question 6

Grid cables are 15 km long with a resistance of 0.20 Ω km^-1, powers wasted as heat in these cables are

A)50 kW
B)60 kW
C)20 kW
D)30 kW

Question 7

Actual velocity of electrons between collisions is

A)1030 m s^-1
B)1020 m s^-1
C)102 m s^-1
D)105 m s^-1

Question 8

By increasing the current, the drift velocity

A)decreases
B)increases
C)remains constant
D)becomes zero

Question 9

Current in a circuit depends on

A)resistance
B)potential difference
C)both A and B
D)e.m.f

Question 10

If direction of current is from positive to negative, then it is called

A)electronic current
B)conventional current only
C)positronic current
D)protonic current

Question 11

A voltmeter arranged across the power supply measures

A)potential difference
B)e.m.f
C)current
D)resistance

Question 12

Particles involved in the movement within material are

A)protons
B)electrons
C)neutrons
D)positrons

Question 13

Phenomena in which a charged body attract uncharged body is called

A)electrostatic induction
B)electric current
C)charge movement
D)magnetic induction

Question 14

An uncharged object has

A)more protons
B)more electrons
C)equal electrons and protons
D)no protons and electrons

Question 15

Fields that act on objects with masses are

A)electric fields
B)magnetic fields
C)force fields
D)gravitational fields

Question 16

Where an electric charge experiences a force, there is an

A)electric field
B)magnetic field
C)electric current
D)conventional current

Question 17

A field that spreads outwards in all directions is

A)radial
B)non radial
C)strong
D)weak

Question 18

At all the points the uniform fields have

A)different strength
B)same strength
C)zero strength
D)infinite strength

Question 19

Electric field strength on a dust particle having charge equal to 8 × 10 - 19 when plates are separated by distance of 2 cm and have a potential difference of 5 kV is {{}}

A)2.0 × 10 -13 N
B)3 N
C)5 N
D)20 N

Question 20

Electric field strength can be defined as

A)E =Q⁄F
B)E = W⁄F
C)E =F⁄Q
D)E =P⁄Q

Question 21

When one material is rubbed against the other, then it becomes electrically

A)neutral
B)charged
C)positively charged
D)negatively charged

Question 22

When an electron is moving horizontally between oppositely charged plates, it will move in the

A)straight line
B)fall directly downwards
C)move towards positive plates
D)curved path

Question 23

E.M.F can be induced in a circuit by

A)changing magnetic flux density
B)changing area of circuit
C)changing the angle
D)all of above

Question 24

A straight wire of length 0.20 m moves at a steady speed of {{}} 3.0 m s^-1 at right angles to the magnetic field of flux density 0.10 T. The e.m.f induced across ends of wire is

A)0.5 V
B)0.06 V
C)0.05 V
D)0.04 V

Question 25

By accelerating the magnet inside the coil, the current in it

A)increases
B)decreases
C)remains constant
D)reverses