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WAEC questions for "Physics :: Fields"
Q1

A statellite in circular motion around the earth does not have 

A

a gravitational force acting on it

B

a uniform velocity

C

an acceleration

D

a centripetal force acting on it

E

Answer: C

Fields
Q2

When a conductor mounted on an insulating stand is charged and left for sometime, the conductor eventually loses all its charges. This is because the 

A

electric charges evaporate from the surface of the conductor 

B

charges are conducted to the earth

C

charges on the conductor are neutralized by opposite charges from the surrounding air

D

charges ionize the surrounding air

E

Answer: C

Fields
Q3

A resistor of resistance R is connected to a battery of negligible internal resistance. If a similar resistor is connected in series with it the 

A

 effective resistance of the circuit is halved

B

total power dissipated is doubled

C

total current in the circuit is halved 

D

terminal voltage is halved

E

Answer: A

Fields
Q4

A cell of e.m.f 1.5V is connected in series with a resistor of resistance 3.0Ω. A voltmeter connected across the cell registers 0.9V. Calculate the internal resistance of the cell.

A

 2.0 Ω

B

3.0Ω

C

5.0Ω

D

6.0Ω

E

Answer: A

Fields
Q5

A wire of sensitivity 4.40 x 10-5 Ωcm2 . Calculate the length of this wire that will be required to make a 4.0Ω resistor .

A

82.50cm

B

68.18cm

C

15.90cm

D

11.94cm

E

Answer: B

Fields
Q6

A battery of e.m.f 12.0V and internal resistance 0.5Ω and 4.0Ω series resistors. Calculate the terminal voltage of the battery

A

13.0V

B

11.0V

C

3.0V

D

1.0V

E

Answer: B

Fields
Q7

If the direction of the current in a straight wire is reversed, the magnetic field

A

remains the same

B

becomes parallel to the wire

C

ceases to exist

D

is oppositely directed

E

Answer: D

Fields
Q8

An ideal step-down transformer steps up

A

power

B

energy

C

current

D

voltage

E

Answer: D

Fields
Q9

An inductor of inductance 1.0 H is connected in series with a capacitor of capacitance 2.0µF in an a.c circuit. Calculate the value of frequency that will make the circuit to resonate

A

112.Hz

B

225.0 Hz

C

353.5 Hz

D

707 .1 Hz

E

Answer: A

Fields
Q10

An ammeter connected to an a.c circuit records 5.5A. The peak current in the circuit is

A

7.8A

B

7.1A

C

3.9A

D

3.5A

E

Answer: A

Fields
Q11

The electric potential at P is given by the expression

A

         Q

       4πεoεrr

B

          Q

4πεoεrr (R + r)

C

                    Q

             4πεoεrr(R-r)

D

                          Q

               4πεoεrr R

E

Answer: A

Fields
Q12

The magnitude of the electric field intensity at P is given  by the expression 

A

               Q

           4πεoεrr2

B

                  Q

     4πεoεrr ( R + r )2

C

                             Q

           4πεoεrr ( R - r)2

D

                          Q

           4πεoεrr R2

E

Answer: A

Fields
Q13

A negatively charged rod is held close to an uncharged metal ball on an insulating stand. The ball will

A

be negatively charged 

B

be positively charged 

C

have an excess of negative charges of the  side nearest the rod 

D

have an excess of positive charges on the side nearest to the rod

E

Answer: B

Fields
Q14

Two bodies each carrying a charge of 2.00 x 10-10 C are 5cm apart. Calculate the magnitude of the force between  the charges  [1/4πεo= 9.00 x Nm2C -2 ]

A

1.44 x 10-7 N

B

7.20 x 10-9 N

C

7.20 x 10-11N

D

1.44 x 10-11 N

E

Answer: A

Fields
Q15

If the charge on an object is measured as 4.0x10-18C, how many excess electrons does the object possess, given that the charge of an electron  is 1.6x10-19C ?

A

18

B

19

C

25

D

37

E

Answer: C

Fields
Q16

Which of the following is a unit of the time rate of flow of electric charges? 

A

Coulomb

B

Ampere

C

Volt

D

Walt

E

Answer: B

Fields
Q17

A wire 1.0m long and with cross-sectional area 2.0 x 10-7 m2  has a resistance of 0.1Ω. CAlculate the electrical conductivity of the wire. 

A

2.0 x 107 Ω-1m-1

B

5.0 x 10Ω-1m-1

C

2.0 x 10Ω-1m-1

D

5.0 x 10Ω-1m-1

E

Answer: A

Fields
Q18

Three capacitors each of capacitance 1.5µF  are connected in series . The total capacitance in the circuit  is 

A

2.0µF

B

1.5µF

C

0.6µF

D

0.5µF

E

Answer: D

Fields
Q19

A voltmeter s a device that 

A

draws high current

B

has a very low resistance  

C

has a very  high reasistance

D

is able to measure both voltage and current

E

Answer: C

Fields
Q20

Which of the following actions will not increase the sensitivity of a moving coil galvanometer? 

A

using a strong temporary magnet

B

increasing the area and number of turns of the coil

C

using  a weak hair spring

D

using a light pointer

E

Answer: C

Fields
Q21

Flemming's right hand rule is also called the 

A

motor rule

B

dynamo rule

C

screw rule

D

thumb rule

E

Answer: C

Fields
Q22

A transformer is required to supply 12 Vrms to operate a toy train set from a 240Vrms. If the number of turns in the secondary coil is 100, calculate the number of turns required in the primary coil

A

5

B

12

C

2000

D

2400

E

Answer: A

Fields
Q23

The diagram here illustrates a bar magnet near a coil connected to a galvanometer. When the magnet is rapidly moved towards the coil.

I. an e.m.f is induced in the coil

II. the galvanometer needle deflects

III. the magnet is attracted by the coil

Which of the statements are correct?

A

I and II only

B

II and III only

C

I and III only

D

I, II and III only

E

Answer: A

Fields
Q24

A direct current of 5A flows through a 0.2H inductor. Calculate the energy stored in the inductor

A

0.5 J

B

1.0J

C

2.5 J

D

5.0 J

E

Answer: C

Fields
Q25

A dry plastic comb used in combing hair was found to attract pieces of paper and dust. The most probable explanation for this phenomenon is that the comb has been given

A

magnetization by induction 

B

electric charges by induction

C

electric charges by conduction

D

electric charges by friction

E

Answer: D

Fields
Q26

Which of the following components is used for storing electric charges?

A

Inductor

B

Resistor

C

Capacitor

D

Electrometer

E

Answer: C

Fields
Q27

Which of the following operations does not represent an action of a force field? 

A

Falling of a mango fruit from the tree

B

Picking of nails using a bar magnet 

C

Repulsion of two like charges 

D

Pushing of a wheel barrow on a level ground

E

Answer: D

Fields
Q28

Calculate the effective resistance between P and Q in the diagram shown above

A

0.75Ω

B

4.00Ω

C

5.00Ω

D

7.00Ω

E

Answer: B

Fields
Q29

A bulb marked 240V, 40W is used for 30 minutes. Calculate the heat generated 

A

320J

B

400J

C

10800J

D

72000J

E

Answer: D

Fields
Q30

Five 80W and three 100W lamps are run for 8 hours. If the cost of energy is ₦5.00 per unit, calculate the cost of running the lamps.

[ 1 unit = 1 kWh] 

A

₦280.00

B

₦28.00

C

₦7.20

D

₦1.44

E

Answer: B

Fields
Q31

The acceleration due to gravity may be defined as the force

A

of attraction of the sun on the earth

B

with which the sun revolves around the earth

C

with which the earth attracts one-kilogram mass

D

of the moon on the earth

E

Answer: C

Fields
Q32

An electron of mass m and charge e enters a uniform electric field between two medal plates P and Q separated by distance d. P is maintained at a potential V while Q is earthed. Determine an expression for the magnitude of the acceleration of the electron through the field

A

ev/md

B

d

mev

C

md/eV

D

e/Vmd

E

Answer: A

Fields
Q33

Which of the following factors does not affect the capacitance of a parallel plate capacitor?

A

Area of the plates

B

Nature of the surfaces of the plates

C

Distance of seperation between the plates

D

Nature of the insulating material between the plates

E

Answer: B

Fields
Q34

The equivalent capacitance of a 3µF capacitor and a 6µF capacitor connected in parallel is

A

2.0 µF

B

3.0µF

C

4.5 µF

D

9.0 µF

E

Answer: D

Fields
Q35

A cell of e.m.f 1.5V and intenal resistance 1.0Ω is connected to two resistors of resistances 2.0Ω and 3.0Ω in series. Calculate the current through the resistors

A

0.25A

B

0.30A

C

0.35A

D

0.50A

E

Answer: A

Fields
Q36

An electric lamp rated 120 W is used on a 240 Vrms. Calculate the resistance of its filament

A

480Ω

B

360Ω

C

60Ω

D

E

Answer: A

Fields
Q37

Which of the following statements about a bar magnent is correct?

A

Iron fillings cling uniformly along the length of the bar magnet

B

The magnet properties are more pronounced at the middle of a magnet

C

It is impossible to have the same poles at the ends of a magnet

D

The magnetic properties are more pronounced at points near the ends of the bar

E

Answer: C

Fields
Q38

The force experienced by a current-carrying conductor moving in a magnetic field is employed in the working of the

I. moving coil ammeter

II. electric bell

III. electric motor.

Which of the statements above are correct?

A

I and II only

B

II and III only

C

I and III only

D

I, II and III

E

Answer: C

Fields
Q39

The ability of a material to store an electric charge when its plates are at different potentials is referred to as its

A

conductane

B

inductane

C

capacitance

D

resistance

E

Answer: C

Fields
Q40

Two capacitors of capacitances 0.4µF and 0.5µF are connected in parallel and charged to a p.d of 50V. Determine the total charge acquired

A

45µC

B

25µC

C

20µC

D

10µC

E

Answer: A

Fields
Q41

A parallel plate capacitor of capacitance 600µF has a potential differevce os 2000V between its plates. Calculate the charge on either plate of the capacitor

A

1.2C

B

3.3C

C

3330.0C

D

120000.0C

E

Answer: A

Fields
Q42

A chemical cell of internal resistance 1Ω supplies electric current to an external resistor of resistance 3Ω. Calculate the efficiency of the cell

A

75%

B

50%

C

33%

D

25%

E

Answer: A

Fields
Q43

An electric lamp is rated 240V, 40W. What is the cost of running the lamp for 72 hours if the electricity authority charges N2.50 per kWh?

A

N7.20

B

N18.00

C

N180.00

D

N720.00

E

Answer: A

Fields
Q44

Which of the following statements explains lost volt in an electric circuit? The

A

total p.d from source to maintain a folw of current through the cuircuit as well as the source

B

p.d to drive current through the circuit components except the source

C

p.d across all external components connected to the source of electricity

D

p.d across the internal resistance of the cell

E

Answer: A

Fields
Q45

A constant wire has  a cross sectional area of 4 x 108m2 and resistivity of 1.1 x10-6Ωm. if a resistor of resistance 11Ω is to be made from wire, calculate the length of the wire required

A

0.4m

B

0.8m

C

2.5m

D

5.0m

E

Answer: A

Fields
Q46

The mass and weight of a body on earth are 8kg and 80N respectively. Determine the mass and weight of the body respectively on a planet where the pull of gravity is 1/8 that on earth

A

8kg, 8N

B

1kg, 10N

C

64kg, 10N

D

8kg, 10N

E

Answer: B

Fields
Q47

Lenz's law of electromagnetic induction states that

A

a force is exerted on a current-carrying  conductor in a magnetic field.

B

electromotive force is induced in a circuit whenever there is a change in the magnetic flux linked with the circuit

C

the magnitude of the induced electromotive force in a circuit is proportional to the rate of change of flux linking the circuit

D

the induced  current in a coil is in such a direction that it sets up a magnetic field which opposes the change producing it

E

Answer: D

Fields
Q48

A bar magnet is placed near and lying along the axis of a solenoid connected to a galvanometer. The pointer of the galvanometer shows no deflection when

A

a magnet is moved away from its stationary solenoid

B

the solonoid is moved away from the stationary magnet

C

the magnet is moved towards the stationary solenoid

D

there is no relative motion between the magnet and solenoid

E

Answer: D

Fields
Q49

An electric motor is a machine that converts

A

mechanical energy into electrical energy

B

electrical energy into mechanical energy

C

high voltage to low voltage

D

low voltage onto high voltage

E

Answer: B

Fields
Q50

Which of the followimg statements is not a reason for using soft iron in making the core of a transformer?  It

A

retains its magnetism for a longtime

B

is easily magnitised

C

reduces energy loss due to hysteresis

D

is easily demagnetised

E

Answer: B

Fields
Q51

Charges on a conductor are

A

evenly distributed over a surface of any shape

B

concentrated on the inner surface of the conductor

C

concentrated at the outer flat surface of the conductor

D

generally concentrated at sharply curved surface

E

Answer: D

Fields
Q52

Which of the following functions is performed by manganese IV oxide in the Leclanche cell?

A

Control of local action

B

Depolarisation of the cell

C

Regulating current flow in the cell

D

Reduction of the internal resistance of the cell

E

Answer: B

Fields
Q53

A car fuse marked 3A operates optimally on a 12V battery. Calculate the resistance of the fuse

A

36.0Ω

B

15.0Ω

C

9.0Ω

D

4.0Ω

E

Answer: D

Fields
Q54

Find the cost of running a 60W lamp for 24 hours, if 1KW costs 5 Naira

A

14.4 Naira

B

12.5 Naira

C

7.2 Naira

D

2.0 Naira

E

Answer: C

Fields
Q55

The quality of electric charge stored in a capacitor is measured in

A

Farad

B

Ampere

C

Coulomb

D

Volt

E

Answer: C

Fields
Q56

Calculate the energy stored in a 20µF capacitator if the p.d between the plates is 40 V

A

3.2 x 10-2J

B

1.6 x 10-2 J

C

8.0 x 10-4 J

D

4.0 x 10-4 J

E

Answer: B

Fields
Q57

Given that the gravitational constant is G, Newton's universal law of gravitation states that the force of attraction between two masses M1 and M2 separated by a distance r is

A

Gr2 M1 M2

B

Gr M1 M2

C

GM1 M2

    r2

D

GM1 M2

     r

 

 

E

Answer: C

Fields
Q58

A charge of 1.6 x 1010C is placed in a uniform electric field of intensity 2.0 x 105 NC-1 . Calculate the magnitude of the electric force exerted on the charge

A

3.2 x 105 N

B

1.8 x105 N

C

3.2 x105 N

D

1.8 x 105 N

E

Answer: C

Fields
Q59

Which of the following statements is not correct?  A

A

magnectic field is a region in which a magnectic force may be detected

B

magnetic line of force is a path along which a magnetic north-pole would move if it were free

C

magnetic fields are scalar qantities

D

neutral points are obtained where the earth's magnetic field is - exactly equal and opposite to that due to a magnet

E

Answer: C

Fields
Q60

The main function of the mouth-piece of a telephone is that it converts sound energy to 

A

mechanical energy

B

electrical energy

C

chemical energy

D

thermal energy

E

Answer: B

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