2000 NECO Physics Past Questions & Answers

Question 1

Which of the following is NOT part of an a.c generator?

Accepted Answer

A. Commutator

Answer

B. Armature

Answer

C. Field magnet

Answer

D. Carbon brushes

Answer

E. Slip rings

Question 2

400g of cold water is added to 200g of water at 70°C. If they are properly mixed and the temperature of the mixture is 30°C. calculate the initial temperature of the cold water. (Neglect the heat absorbed by the container)

Accepted Answer

A. 10°C

Answer

B. 15°C

Answer

C. 20°C

Answer

D. 30°C

Answer

E. 40°C

Question 3

An element of nuclear number A and proton number Z emits an alpha particle from its nucleus. The nucleon number and the proton number of the new element formed are respectively

Accepted Answer

E. (A – 4) and (Z – 2)

Answer

A. (A – 2) and (Z – 2)

Answer

B. (A + 4) and (Z + 2)

Answer

C. (A– 4) and (Z+2)

Answer

D. (A+ 4) and (Z – 2)

Question 4

The image obtained on the screen of a pin-hole camera becomes less sharply defined when the

Accepted Answer

E. pin-hole is made larger.

Answer

A. object is moved farther from the pin-hole

Answer

B. screen is moved farther from the pin-hole

Answer

C. object is made smaller

Answer

D. illumination is made more intense

Question 5

Which of the following is used in a nuclear reactor to slow down fast moving neutrons?

Accepted Answer

A. graphite rods

Answer

B. carbon dioxide gas

Answer

C. liquid sodium metal

Answer

D. concrete shield

Answer

E. boron rods

Question 6

Which of the following is/are TRUE of nuclear fission? I. A heavy nucleus is split into two nuclei of comparable masses II. Two light nuclei are joined together to form a heavier nucleus III. The total mass of the products is less than that of the reactants

Accepted Answer

D. I and III only

Answer

A. I only

Answer

B. II only

Answer

C. III only

Answer

E. II and III only

Question 7

A particle of charge q and mass m moving with a velocity v enters a uniform magnetic field B in the direction of the field. The force on the particle is

Accepted Answer

C. Bqvm

Answer

A. Bqv

Answer

B. Bq$\frac{v}{m}$

Answer

D. mv$\frac{B}{q}$

Answer

E. $\frac{mv}{Bq}$

Question 8

A man at the back of a crowd watches a parade by holding a plane mirror just above his head. The parade passes 6 metres behinde his head and the mirror is 0.25m in front of the man. How far does the image in the mirror appear to be from the man?

Accepted Answer

A. 6.50m

Answer

B. 6.25m

Answer

C. 6.00m

Answer

D. 5.75m

Answer

E. 5.50m

Question 9

Two 2.0Ω resistors can be combined circuit to give an overall resistance of

Accepted Answer

D. either 1.0Ω or 4.0 Ω

Answer

A. 0.5Ω only

Answer

B. 1.0 Ω only

Answer

C. either 0,5Ω or 1.0 Ω

Answer

E. either 0.5Ω, 1.0Ω or 4.0Ω

Question 10

The image is a plane mirror is

Accepted Answer

D. upright, virtual with a magnificent of 1

Answer

A. inverted, real with a magnificant of $\frac{1}{2}$

Answer

B. inverted, virtual with a magnification of 1

Answer

C. inverted, real with a magnification of 2

Answer

E. upright, real with a magnification of 2

Question 11

An electric bell operated within an evacuated bell jar enables us to infer correctly that

Accepted Answer

C. light waves do not require a medium for transmission but sound waves do

Answer

A. light waves require a medium for transmission

Answer

B. sound waves do not require a medium for transmission

Answer

D. light waves travel much faster than sound waves

Answer

E. light waves and sound waves travel at the same speed

Question 12

The length of a side of a metallic cube at 20° C is 5.0cm. Given that the linear expansively of the metal is 4.0 × 10-5K-1, find the volume of the cube at 120° C

Accepted Answer

E. 126.50cm3

Answer

A. 124.50cm3

Answer

B. 125.00cm3

Answer

C. 126.00cm3

Answer

D. 126.25cm3

Question 13

The half-life of a radioactive substance is 2 seconds. Calculate the decay constant.

Accepted Answer

D. 0.347s-1

Answer

A. 2.890 s-1

Answer

B. 1 .445 s-1

Answer

C. 0.576 s-1

Answer

E. 0.152 s-1

Question 14

Which of the following pairs of light rays shows the widest separation in the spectrum of white light?

Accepted Answer

C. Red and indigo

Answer

A. Red and blue

Answer

B. Orange and green

Answer

D. Violet and green

Answer

E. Yellow and red

Question 15

A wave travels a distance of 20 cm in 3s. The distance between successive crests of the wave is 4cm. What is the frequency of the wave?

Accepted Answer

B. 1.67Hz

Answer

A. 0.60Hz

Answer

C. 7.50Hz

Answer

D. 15.00Hz

Answer

E. 26.67Hz

Question 16

A boy ran a distance of 200m in 24s. His average speed was 8.3$ms^{-1}$. Which of the following is correct about the units in which the statements above are expressed?

Accepted Answer

D. Two of the units are fundamental and one derived.

Answer

A. All the units are fundamental.

Answer

B. All the units are derived

Answer

C. All the units except one are S.I units

Answer

E. None of the units is S.I units.

Question 17

The helium isotope $^3_2He$

Accepted Answer

B. has two protons and one neutron

Answer

A. has three pro tons and two neutrons

Answer

C. has two protons and three neutrons

Answer

D. has one proton and two neutrons

Answer

E. cannot exist because it has the same mass number as tritium

Question 18

What is the coefficient of static friction between a load of mass 2kg and a horizontal surface, if the limiting frictional force is 10N? (g = 10 $ms^{-2}$)

Accepted Answer

B. 0.5

Answer

A. 0.2

Answer

C. 2

Answer

D. 5

Answer

E. 8

Question 19

A man standing 510m away from a wall sounds a whistle. The echo from the wall reaches him 3s later. Calculate the velocity of sound in air.

Accepted Answer

B. 340 $ms^{-1}$

Answer

A. 170 $ms^{-1}$

Answer

C. 680 $ms^{-1}$

Answer

D. 765 $ms^{-1}$

Answer

E. 1530 $ms^{-1}$

Question 20

I. A scalar quantity has only magnitude II. A scalar quantity has both magnitude and direction III. A vector quantity has both magnitude and direction IV. A vector quantity has only magnitude. Which of the above statement is/are correct?

Accepted Answer

C. l and III only

Answer

A. I only

Answer

B. l and II only

Answer

D. II and III only

Answer

E. II and III only

Question 21

If a positively charged glass-rod is used to charge an electroscope X by contact and an electroscope Y by induction, then

Accepted Answer

D. X will be positively charged and Y negatively charged

Answer

A. X and Y will be negatively charge

Answer

B. X and Y will be positively charged

Answer

C. X will be negatively charged and Y positively charged

Answer

E. X will be positively charged and Y will remain uncharged

Question 22

An electric iron rated 250 V has a coil of resistance 125Ω. What is the cost of using it for I hour at 10k per kWh?

Accepted Answer

C. 5.00k

Answer

A. 1.25k

Answer

B. 2.50k

Answer

D. 10.00k

Answer

E. 20.00k

Question 23

The heat from a fire in a closed room reaches someone far away in the room, mainly by

Accepted Answer

D. radiation

Answer

A. reflection

Answer

B. diffusion

Answer

C. conduction

Answer

E. convection

Question 24

When a metal is heated to a high temperature, electrons are emitted from its surface. The process is known as

Accepted Answer

B. thermionic emission

Answer

A. photoelectric effect

Answer

C. field emission

Answer

D. secondary emission

Answer

E. radioactive emission

Question 25

Calculate the peak voltage of a mains supply of r.ms. value 220V.

Accepted Answer

E. 311 V

Answer

A. 121 V

Answer

B. 156 V

Answer

C. 225 V

Answer

D. 240 V

Question 26

When a lever is in equilibrium, under the action of two or more forces, the algebraic sum of the moments of the forces about the point of support is

Accepted Answer

E. equal to zero

Answer

A. anti-clockwise

Answer

B. clockwise

Answer

C. equal to the product to the forces

Answer

D. numerically equal to the total forces acting

Question 27

Which of the following is/areNOT affected by a magnetic field? I. Alpha particle II. Cathode rays III. Neutrons

Accepted Answer

C. III only

Answer

A. I only

Answer

B. II only

Answer

D. I and II only

Answer

E. I,II & III

Question 28

Two forces forming a couple are separated by a distance of 25cm. If one of the forces equals 40N, what is the moment of the couple?

Accepted Answer

C. 10 Nm

Answer

A. 1000 Nm

Answer

B. 500 Nm

Answer

D. 5 Nm

Answer

E. 1.6 Nm

Question 29

The image formed by a converging lens of focal length is of a distance of 2f from the lens. Calculate the lateral magnification produced

Accepted Answer

B. 1

Answer

A. 0.5

Answer

C. 1.5

Answer

D. 2

Answer

E. 3

Question 30

A piece of stone weights 180 N in air and 150 N in a beaker containing 160 N of methylated spirit. What is the up thrust exerted on the stone?

Accepted Answer

C. 30N

Answer

A. 50N

Answer

B. 40N

Answer

D. 20N

Answer

E. 10N

Question 31

An astronomical telescope which is being used to view a very distant object is said to be in normal adjustment if

Accepted Answer

D. the foci dl the objective and the eye-piece coincide between the lenses

Answer

A. the final image is at the near-point

Answer

B. the image formed by the objective is before the focus of the eye piece

Answer

C. the angular magnification is the ratio of the focal length of the eye-piece lens to that of the objective

Answer

E. the distance between the objective lens and the eye-piece is equal to the difference between their focal lengths.

Question 32

If the first position of resonance in a resonance tube is 18.0cm from the open end, the distance from the open end to the next position of resonance will be

Accepted Answer

E. 54.0cm

Answer

A. 24.0cm

Answer

B. 27.0cm

Answer

C. 36.0cm

Answer

D. 45.0cm

Question 33

A radioactive substance has a half-life of 3 minutes. After 9 minutes, the count rate was observed to be 200. What was the count rate at zero time?

Accepted Answer

C. 1600

Answer

A. 200

Answer

B. 1200

Answer

D. 2400

Answer

E. 4800

Question 34

The force exerted on a charged body in an electric field depends on I. the charge on the body II. the electric field intensity III. the square of the mass of the body

Accepted Answer

C. I and II only

Answer

A. I only

Answer

B. II only

Answer

D. I and III only

Answer

E. II and III only

Question 35

In a simple pendulum experiment, a boy observed that the times for 30 oscillations are 70.0s, 72.0s and 67.0s respectively. Calculate the mean period of oscillation of the pendulum.

Accepted Answer

C. 2.32s

Answer

A. 0.14s

Answer

B. 0.43s

Answer

D. 2.40s

Answer

E. 6.97s

Question 36

A gas occupies a certain volume at 27°C. At what temperature will its volume be twice times the original volume assuming that its pressure remains constant?

Accepted Answer

D. 327°C

Answer

A. 54°C

Answer

B. 108°C

Answer

C. 150°C

Answer

E. 600°C

Question 37

Which of the following statements about evaporation and boiling is FALSE?

Accepted Answer

E. The rate of evaporation does not depend on temperature.

Answer

A. Evaporation may take place at any temperature.

Answer

B. In evaporation, vapour escapes only from the surface of a liquid

Answer

C. The temperature remains constant as long as the liquid is boiling

Answer

D. The temperature at which boiling takes place can be altered by changing the external pressure

Question 38

To keep a lorry moving at a constant speed v, requires power p, from the engine. The force provided by the engine is

Accepted Answer

C. $\frac{p}{v}$

Answer

A. $\frac{1}{2}$v

Answer

B. pv

Answer

D. pv2

Answer

E. $\frac{p}{v^2}$

Question 39

A block of a substance X will sink in a liquid V but float liquid Z. Which of the following statements is NOT correct about the densities of the three substances?

Accepted Answer

E. If liquids V and Z do not mix, liquid Z will float on liquid V.

Answer

A. Density of liquid Z is greater than that of X

Answer

B. Density of liquid V is less than that of liquid X

Answer

C. Density of liquid Y is less than that of liquid Z

Answer

D. Liquid Z has the greatest density of all the three substances.

Question 40

A boy moving with a velocity of 3 $ms^{-1}$ is brought to rest by a constant force after travelling 15m. Calculate the retardation.

Accepted Answer

B. 0.30$ms^{-2}$

Answer

A. 0.15$ms^{-2}$

Answer

C. 0.60$ms^{-2}$

Answer

D. 3.33$ms^{-2}$

Answer

E. 6.66$ms^{-2}$

Question 41

The specific heat of a substance in the solid state is C1; its specific beat in the liquid state is C2 and its latent heat of fusion is L. If a mass M of the substance is changed from the solid state at temperature T, to the liquid state, also at temperature T, the amount of heat required will be

Accepted Answer

B. ML

Answer

A. M(C1 ÷ C2) x T

Answer

C. L

Answer

D. M(C1 + C2) × T ÷ ML

Answer

E. ML(C1 + C2 ÷ 2) × T

Question 42

The clinical thermometer differs from other mercury-in-glass thermometers because it has I. a constriction II. a wide range III. a short range IV. a narrow bore. Which of the above are correct?

Accepted Answer

E. I, III and IV only

Answer

A. I and II only

Answer

B. I and III only

Answer

C. III and IV only

Answer

D. I,II and III only

Question 43

When electrical power is transmitted over long distances, the voltage is stepped up so that

Accepted Answer

E. the energy waste may be minimised as the current is lowered.

Answer

A. the resistance of the wire may be increased proportionately to the potential difference

Answer

B. the time of transmissions between the generating and the receiving stations may be reduced

Answer

C. there is increased current to produce brighter lights.

Answer

D. the rate of electrical consumption is increased.

Question 44

The unit of inductance is

Accepted Answer

D. Henry

Answer

A. Weber

Answer

B. Telsa

Answer

C. Hertz

Answer

E. Farad

Question 45

A solid weights 5.0 N in air, 4.2 N in water and 4.4 N in liquid Y. Calculate the relative density of liquid Y.

Accepted Answer

A. 0.75

Answer

B. 0.88

Answer

C. 0.95

Answer

D. 1.13

Answer

E. 1.33

Question 46

The smallest unit on the sleeve of a micrometer screw gauge is 0.5mm. There are fifty divisions on the thimble of the screw gauge. What is the smallest length that can be measured with this instrument?

Accepted Answer

D. 0.001cm

Answer

A. 0.05cm

Answer

B. 0.01cm

Answer

C. 0.005cm

Answer

E. 0.0001cm

2000 NECO Physics Past Questions

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