2015 - JAMB Physics Past Questions and Answers - page 4

Heat capacity (o) = mass (kg) specific heat of a substance (C₂)

i.e Q = MC

where Q = 40 J/L, m = ?(380 J/Kgk)

40 = m × 380

m = 0.11kg (Approx)

Using the equation

S = ut + ½ gt²

H = s = 20m, t = ?

G =10m/s², u = 0m/s

20 = 0 × t × ½ × 10 t

20 = 5t

i.e 5t² = 20

t = 20/5 = 4

t = 4 (squaring both sides)

√ t² = √4

= 2sec

∴ t = 2sec

Velocity Ratio (V.R) = distance moved by the effort (x)÷ distance moved by the load (y)

i.e. V.R = x/y

v. R = 5, x/y = ?

i.e x/y = 5/1; , where x = 5, y = 1

x : y = 5 : 1

Mechanical advantage (M.A) of a machine is the ratio of its load to effort

Mathematically

Mechanical advantage (M.A) = Load (L) ÷ Effort (E)

In symbol M.A = L/E

Note:Mechanical (advantages has no S.I unit)

If M.A = 4 then,

L/E = 4/1

The ratio of load to effort = 4 : 1 respectively

A gas thermometers are more besting use to achieve an accurate temperature than others, such as liquid in glass thermometers such as mercury, clinical and alcohol thermometer

The correct answer is A. Both objects will reach the ground at the same time. Here's why: * **Neglecting Air Resistance:** The question explicitly states to neglect air resistance. In a vacuum (or when air resistance is negligible), the only force acting on the objects is gravity. * **Acceleration due to Gravity:** Gravity causes all objects to accelerate downwards at the same rate, regardless of their mass or weight. This acceleration is approximately 9.8 m/s². * **Equal Time of Descent:** Since both objects experience the same acceleration due to gravity and are released from the same height, they will take the same amount of time to reach the ground.

M= 3kg, r = 0.7m, v = 2m/s

v = wr

w = angular velocity

r = radius in an tangential circular

v = speed of an object

W = V/δ = 2/ 0.7 = 2.85

W = 2.853rads–1 (total interest whole number)

W = &approx.; 3rads–1Angular velocity (w) = 3rads^–1

Microscope is used for nearby object

Electron: A sub–atomic particle haring a negative charge and orbiting the nucleus (note: the symbol 0–1e represent the particle of an electrons.)

Wavelength (Λ) = 10 ^-13m

Speed of X-ray = speed of light C = 3×10³m/s

Frequently (f) = ?

Using V = fΛ (or (– f π for electromagnetic wave)

f = c/Λ = 3 × 10⁸ ÷ 10^-13 = 3 × 10³ × 10³

= 3 × 10¹³ × 10¹³

= 3 × 10²¹HZ