2024 - JAMB Physics Past Questions and Answers - page 1

Given:

• Length: 10 cm = 0.1 m
• Breadth: 5 cm = 0.05 m
• Height: 2 cm = 0.02 m
• Density: 1000 kg/m³
• Gravity: g = 10 m/s²

Step 1: Volume

\( V = L \times B \times H = 0.1 \times 0.05 \times 0.02 = 0.0001 \, \text{m³} \)

Step 2: Mass

\( m = \rho \times V = 1000 \times 0.0001 = 0.1 \, \text{kg} \)

Step 3: Weight

\( W = m \times g = 0.1 \times 10 = 1 \, \text{N} \)

Step 4: Pressure

Base area: \( A = L \times B = 0.1 \times 0.05 = 0.005 \, \text{m²} \)

\( P = \frac{W}{A} = \frac{1}{0.005} = 200 \, \text{N/m²} \)

Work is done when a force causes a displacement.

• A: The man is applying a force, but there is no displacement of the load (it remains stationary).
• B: The woman applies a force, but there's no displacement.
• C: The boy applies a force to climb, and there is a displacement in the vertical direction. Thus, work is done.
• D: The man applies a force, but the tanker does not move (no displacement).

Acceleration is defined as the rate of change of velocity. Velocity includes both speed and direction. Therefore, when a bus is accelerating, it must be changing its velocity. This change can involve a change in speed, a change in direction, or both.

The relationship between real depth and apparent depth is given by the refractive index formula:

Refractive index (n) = Real depth / Apparent depth

Given:

• Apparent depth = 10 cm
• Refractive index of water (n) = 1.33

Real depth = Refractive index x Apparent depth = 1.33 x 10 cm = 13.3 cm

Here's how to approach this problem:

1. Understand the Circuit: The circuit appears to be a Wheatstone bridge. The galvanometer is in the middle branch.
2. Wheatstone Bridge Balance Condition: For the galvanometer to measure 2 A, there must be a current through it, which means the bridge is not balanced.
3. Analyze the Circuit: Since the galvanometer measures 2 A, the bridge is not balanced. More information is needed for the exact value of R. Assuming an ideal case, one of the given options can be taken as the solution.

The power of a lens is the reciprocal of its focal length in meters.

1. Convert focal length to meters: 20 cm = 0.20 m
2. Calculate power: Power (P) = 1 / focal length (f) = 1 / 0.20 m = 5.0 D (diopters)

The energy of a moving car is primarily due to its motion.

• Kinetic energy: The energy an object possesses due to its motion.
• Mechanical energy: Sum of potential and kinetic energy. While the car possesses mechanical energy, the primary form due to motion is kinetic.
• Electrical energy: Involves the flow of electric charge, not relevant here.
• Potential energy: Stored energy due to position or condition, not motion.

A concave mirror is the best choice for a shaving mirror because it can produce a magnified, upright image when the object (your face) is within the focal length. This makes it easier to see details and perform tasks like shaving. Convex mirrors produce diminished images, plane mirrors produce images the same size, and parabolic mirrors are used for focusing light, not image magnification.

Here's how to solve the problem:

1. Identify the formula: Q = mcΔT, where m = mass, c = specific heat capacity, ΔT = change in temperature.
2. Convert mass to kilograms: m = 60 g = 0.06 kg
3. ΔT = 75 - 35 = 40 ºC
4. Q = 0.06 kg x 460 J/kg·K x 40 K = 1104 J

Here's how to solve this problem:

1. Photon energy formula: E = hc / λ, where h = 6.63 x 10^-34 Js, c = 3.0 x 10⁸ m/s, λ = 5.68 x 10^-6 m.
2. Plug in values: E = (6.63 x 10^-34 x 3.0 x 10⁸) / 5.68 x 10^-6
3. Calculate: E ≈ 3.5 x 10^-20 J