Physics 2024 Jamb Examination
Physics 2024 Jamb Examination
Question 31
Which of the following is the best as shaving mirror?
A concave mirror is used as a shaving mirror because when an object (the face) is placed between the pole and the principal focus of the mirror, it produces an upright, magnified, and virtual image. This allows the user to see a clearer, enlarged view for grooming.
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Question 32
A refrigerator uses 150W. If it is kept on for 336 hours non-stop, what is the energy consumed in KWh?
Electrical energy consumed (E) in Kilowatt-hours (KWh) is calculated as:\[ E = \frac{\text{Power (W)} \times \text{Time (h)}}{1000} \]Given:
Power = \( 150\,\text{W} \)
Time = \( 336\,\text{h} \)
\[ E = \frac{150 \times 336}{1000} = \frac{50400}{1000} = 50.40\,\text{KWh} \]
Power = \( 150\,\text{W} \)
Time = \( 336\,\text{h} \)
\[ E = \frac{150 \times 336}{1000} = \frac{50400}{1000} = 50.40\,\text{KWh} \]
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Question 33
What is the inductance reactance of a coil of 7H when connected to a 50Hz a.c circuit?
Inductive reactance (\( X_L \)) is calculated using the formula:\[ X_L = 2\pi f L \]Given:
Inductance \( L = 7\,\text{H} \)
Frequency \( f = 50\,\text{Hz} \)
Take \( \pi \approx \frac{22}{7} \) for easier calculation:\[ X_L = 2 \times \frac{22}{7} \times 50 \times 7 \]\[ X_L = 2 \times 22 \times 50 = 2200\,\Omega \]
Inductance \( L = 7\,\text{H} \)
Frequency \( f = 50\,\text{Hz} \)
Take \( \pi \approx \frac{22}{7} \) for easier calculation:\[ X_L = 2 \times \frac{22}{7} \times 50 \times 7 \]\[ X_L = 2 \times 22 \times 50 = 2200\,\Omega \]
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Question 34
If a charge ion goes through a combined electric field E and magnetic field B, the resultant emergent velocity of the ion is
In a velocity selector, an electric field (E) and a magnetic field (B) are applied perpendicularly to each other. An ion will pass through undeflected (emerge) only if the electric force (\( F_e = qE \)) equals the magnetic force (\( F_m = qvB \)):\[ qE = qvB \implies v = \frac{E}{B} \]
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Question 35
In electrolysis, when same quantity of electricity is passed through different electrolytes, mass of substances deposited is proportional to
This is Faraday's Second Law of Electrolysis. It states that when the same quantity of electricity is passed through several electrolytes, the mass of the substances deposited at the electrodes is directly proportional to their respective chemical equivalents (equivalent weights).
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Question 36
If the rate of evaporation is y, and the rate of condensation is x, then, a vapour is saturated when
A saturated vapour exists in a state of dynamic equilibrium with its liquid. At this stage, the rate of evaporation (y) is exactly equal to the rate of condensation (x).
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Question 37
The degree of precision of a vernier caliper is
The least count of a standard vernier caliper is 0.1 mm, which is equivalent to 0.01 cm.
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Question 38
According to kinetic theory of gases, the pressure exerted by the gas on the wall is equal
Pressure is force per unit area. From Newton’s second law, force is the rate of change of momentum, so gas pressure is the rate at which momentum is transferred to the container walls per unit area.
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Question 39
The property by which a material returns to its original shape after the removal of force is called
Elasticity is the ability of a material to regain its original shape after the deforming force is removed.
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Question 40
The energy in a moving car is an example of
Kinetic energy is the energy possessed by an object due to its motion.
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