JAMB Physics 2023

Which of the following represents the correct precision if the length of a piece of wire is measured with a meter rule?

A) 35mm B) 35.0mm C) 35.00mm D) 35.01mm

Correct Answer: B) 35.0mm

Which of the following is most strongly deflected by a magnetic field?

A) γ-rays B) α-rays C) β-particles D) X-rays

Correct Answer: C) β-particles

A substance has a half-life of 3min. After 6mins, the count rate was observed to be 600. What was its count rate at zero time?

A) 200 B) 1200 C) 1600 D) 2400

Correct Answer: D) 2400

A light of energy 5eV falls on a metal and electrons with a maximum kinetic energy of 2eV are ejecteD) The work function of the metal is

A) 0.4eV B) 2.5eV C) 3.0eV D) 7.0eV

Correct Answer: C) 3.0eV

If an object is placed in front of two mirrors inclined at 90°, how many images will be formed?

A) Five B) Four C) Three D) Two

Correct Answer: C) Three

A 12V battery has an internal resistance of 0.5Ω. If a cable of 1.0Ω resistance is connected across the terminals of the battery, the current drawn from the battery is

A) 16.0A B) 8.0A C) 0.8A D) 0.4A

Correct Answer: B) 8.0A

If two parallel wires carry currents flowing in the same direction, the conductors will

A) attract each other B) repel each other C) both move in the same direction D) have no effect on each other

Correct Answer: A) attract each other

From the generating station to each sub-station, power is transmitted at a very high voltage so as to reduce

A) eddy current loss B) hysteresis loss C) heating in the cables D) magnetic flux leakage

Correct Answer: C) heating in the cables

Two tuning forks of frequencies 256Hz and 260Hz are sounded close to each other. What is the frequency of the beats produced?

A) 516Hz B) 258Hz C) 4Hz D) 300Hz

Correct Answer: C) 4Hz

The eye controls the amount of light reaching the retina by adjusting the

A) cornea B) iris C) retina D) optic nerve

Correct Answer: B) iris

Which of the following is a set of vectors?

A) force, mass and momentum B) acceleration, velocity and momentum C) mass, weight and density D) mass, volume and density

Correct Answer: B) acceleration, velocity and momentum

A catapult used to hold a stone of mass 500g is extended by 20cm with an applied force, F. If the stone leaves with a velocity of 40m/s, the value of F is

A) 4.0 × 10² N/m² B) 2.0 × 10³ N C) 4.0 × 10³ N D) 4.0 × 10⁴ N

Correct Answer: B) 2.0 × 10³ N

A nuclear reaction initiated by adding neutron is called

A) nuclear fission B) nuclear fusion C) nuclear enrichment D) radioactivity

Correct Answer: A) nuclear fission

The resultant of two forces acting on an object is maximum if the angle between them is

A) 45° B) 0° C) 90° D) 180°

Correct Answer: B) 0°

200g of water at 90°C is mixed with same quantity of water at 30°C) What is the final temperature?

A) 50°C B) 60°C C) 70°C D) 80°C

Correct Answer: B) 60°C

The equation P^XV^YT^Z = constant is Charles law when

A) x=1, y=1, z=1 B) x=0, y=1, z=-1 C) x=1, y=0, z=-1 D) x=0, y=1, z=1

Correct Answer: B) x=0, y=1, z=-1

The thermometric substance of an absolute thermometer is

A) alcohol B) mercury C) helium D) platinum

Correct Answer: B) mercury

Dispersion of light by a glass prism is due to the

A) different hidden colours of the glass B) different speeds of various colours in glass C) defect in the glass D) high density in glass

Correct Answer: B) different speeds of various colours in glass

When an atom loses or gains a charge, it becomes

A) an electron B) an ion C) a neutron D) a proton

Correct Answer: B) an ion

To convert an ac dynamo to dc dynamo, the

A) number of turns of the coil is increased B) slip rings are replaced with a split-ring commutator C) number of turns of the coil is reduced D) split-ring commutator is replaced with slip rings

Correct Answer: B) slip rings are replaced with a split-ring commutator

The unit of inductance is the

A) Farad B) Hertz C) Henry D) Coulomb

Correct Answer: C) Henry

A machine whose efficiency is 60% has a velocity ratio of 5. If a force of 500N is applied to lift a load of P(N), what is the magnitude of P?

A) 750N B) 4166N C) 500N D) 1500N

Correct Answer: D) 1500N

A mass of gas at 7°C and 70cm of mercury has a volume of 1200cm³. Determine its volume at 27°C and a pressure at 75cm of mercury.

A) 1200cm³ B) 1378cm³ C) 4320cm³ D) 4629cm³

Correct Answer: A) 1200cm³

A beam of light is incident from air to water at an angle of 30°. Find the angle of refraction if the refractive index of water is 4/3.

A) 15° B) 18° C) 22° D) 240°

Correct Answer: C) 22°

The wavelength of signal from a radio transmitter is 1500m and the frequency is 200KHz. What is the velocity of the propagation?

A) 3 × 10⁸ ms⁻² B) 7 × 10³ ms⁻² C) 3 × 10⁴ ms⁻² D) 7ms⁻²

Correct Answer: A) 3 × 10⁸ ms⁻²

Find the frequencies of the first three harmonics of a piano string of length 1.5m, if the velocity of the string is 120m/s.

A) 40Hz, 80Hz, 120Hz B) 180Hz, 360Hz, 540Hz C) 80Hz, 160Hz, 240Hz D) 360Hz, 180Hz, 90Hz

Correct Answer: A) 40Hz, 80Hz, 120Hz

The resistance of a piece of wire of length 20 cm and cross-sectional area 8 × 10⁻⁵ m² and resistivity 4 × 10⁻⁷ Ωm is

A) 1.0 Ω B) 10.0 Ω C) 400.0 Ω D) 1.0 × 10⁻¹³ Ω

Correct Answer: D) 1.0 × 10⁻¹³ Ω

An electric device is rated 2000W, 250V. The correct fuse rating of the device is

A) 8A B) 9A C) 7A D) 6A

Correct Answer: A) 8A

Determine the inductive reactance when a 30.0mH inductor with negligible resistance is connected to a 1.3KHz oscillator

A) 39.0Ω B) 122.5Ω C) 245.0Ω D) 39KΩ

Correct Answer: C) 245.0Ω

The half-life of a radioactive element is 9days. Calculate the fraction that remains after 36days.

A) 1/32 B) 1/16 C) 1/4 D) 15/32

Correct Answer: B) 1/16

The energy stored in an inductor of inductance 5mH when a current of 6A flows through it is

A) 9.0 × 10⁻³ J B) 9.0 × 10⁻² J C) 1.4 × 10⁻² J D) 1.8 × 10⁻² J

Correct Answer: B) 9.0 × 10⁻² J

An electric heater with a pd of 240V connected across its terminals has a total resistance of 960Ω. Calculate power range of the heater

A) 0.25 W B) 4.00 W C) 38.40 W D) 60.00 W

Correct Answer: D) 60.00 W

The time it will take a certain radioactive material with a half-life of 50 to reduce to of its original number is

A) 250 days B) 150 days C) 300 days D) 200 days

Correct Answer: A) 250 days

The unit of moment of a couple can be expressed in

A) Nm⁻¹ B) Nm⁻² C) Nm D) Nm²

Correct Answer: C) Nm

The resultant of two forces 12N and 5N is 13N. What is the angle between the two forces?

A) 0° B) 45° C) 90° D) 180°

Correct Answer: C) 90°

A body of mass 12Kg traveling at 4.2ms⁻¹ collides with another body of mass 18Kg at rest. Calculate their common velocity if the two bodies coalesce after collision.

A) 1.5ms⁻¹ B) 1.4ms⁻¹ C) 2.1ms⁻¹ D) 1.7ms⁻¹

Correct Answer: D) 1.7ms⁻¹

When the vapour of a substance is in equilibrium with its own liquid, it is said to be

A) gaseous B) liquified C) diffused D) saturated

Correct Answer: D) saturated

If the pressure of 100cm³ of an ideal gas is doubled while its Kelvin temperature is halved, then the new volume of the gas is

A) 25cm³ B) 50cm³ C) 100cm³ D) 200cm³

Correct Answer: A) 25cm³

The eye controls the amount of light reaching the retina by adjusting the

A) cornea B) iris C) retina D) optic nerve

Correct Answer: B) iris

Transverse waves can be distinguished from longitudinal waves using the characteristics of

A) diffraction B) refraction C) polarization D) reflection

Correct Answer: C) polarization