JAMB - PHYSICS CHALLENGE

1    The inner diameter of a test tube can be measured accurately using a

A. micrometer screw guage

B. pair of dividers

C. metre rule

D. pair of vernier calipers

2

Two bodies have masses in the ratio 3:1. They experience forces which impart to them acceleration in the ratio 2:9 respectively. Find the ratio of forces the masses experienced.

A. 1 : 4

B. 2 : 1

C. 2 : 3

D. 2 : 5

3

Particles of mass 10^-2kg is fixed to the tip of a fan blade which rotates with angular velocity of 100rad^-1. If the radius of the blade is 0.2m, the centripetal force is

A. 2 N

B. 20 N

C. 200 N

D. 400 N

4

a lead bullet of mass 0.05kg is fired with a velocity of 200ms^-1 into a lead block of mass 0.95kg. Given that the lead block can move freely, the final kinetic energy after impact is

A. 50 J

B. 100 J

C. 150 J

D. 200 J

5

A ball of mass 0.1kg is thrown vertically upwards with a speed of 10ms^-1 from the top of a tower 10m high. Neglecting air resistance, its total energy just before hitting the ground is

(take g = 10ms^-2)

A. 5 J

B. 10 J

C. 15 J

D. 20 J

A car of mass 800kg attains a speed of 25m/s in 20 secs. The power developed in the engine is

A. 1 . 25 x 10⁴ W

B. 2 . 50 x 10⁴ W

C. 1 . 25 x 10⁶W

D. 2 . 50 x 10⁶ W

7

When the brakes in a car are applied, the frictional force force on the tyres is

A. is a disadvantage because it is in the direction of the motion of the car

B. is a disadvantage because it is in the opposite direction of the motion of the car

C. is an advantage because it is in the direction of the motion of the car

D. is an advantage because it is in the opposite direction of the motion of the car

8

If the stress on a wire is 10⁷NM^-2 and the wire is stretched from its original length of 10.00 cm to 10.05 cm. The young's modulus of the wire is

A. 5 . 0 x 10⁴ Nm^-2

B. 5 . 0 x 10⁵ Nm^-2

C. 2 . 0 x 10⁸ Nm^-2

D. 2 . 0 x 10⁹ Nm^-2

9

A solid weigh 10 .00 N in air, 6 N when fully immersed in water and 7 . 0 N when fully immersed in a liquid X. Calculate the relative density of the liquid, X.

A. 5/3

B. 4/3

C. 3/4

D. 7/10

10

When temperature of a liquid increases, its surface tension

A. Decreases

B. Increases

C. Remain Constant

D. Increases then decreases

A gas at a volume of V₀ in a container at pressure P₀ is compressed to one-fifth of its volume. What will be its pressure if the magnitude of its original temperature T is constant?

A. P₀/5

B. 4P₀/5

C. P₀

D. 5P₀

12

A piece of substance of specific head capacity 450JKg^-1K^-1 falls through a vertical distance of 20m from rest. Calculate the rise in temperature of the substance on hitting the ground when all its energies are converted into heat. [g = 10ms^-2]

A. 2/9°C

B. 4/9°C

C. 9/4°C

D. 9/2°C

13

I. A liquid boils when its saturated vapour pressure is equal to the external pressure
II. Dissolved substances in pure water lead to increase in the boiling point.
III. When the external pressure is increased, the boiling point increases.
IV. Dissolved substances in pure water decrease the boiling point.

Which combination of the above are peculiarities of the boiling point of a liquid?

A. I, II and III

B. I, II, III and IV

C. I, II and IV

D. II, III and IV

14

The temperature gradient across a copper rod of thickness 0.02m, maintained at two temperature junctions of 20°C and 80°C respectively is

A. 3.0 x 10²Km^-1

B. 3.0 x 10³Km^-1

C. 5.0 x 10³Km^-1

D. 3.0 x 10⁴Km^-1

15

Calculate the mass of ice that would melt when 2kg of copper is quickly transferred from boiling water to a block of ice without heat loss;
Specific heat capacity of copper = 400JKg^-1K^-1
Latent heat of fusion of ice = 3.3 x 10⁵JKg^-1

A. 8/33kg

B. 33/80kg

C. 80/33kg

D. 33/8kg

16

The equation of a wave travelling along the positive x-direction is given by;
y = 0.25 x 10^-3 sin (500t - 0.025x).
Determine the angular frequency of the wave motion.

A. 0.25 x 10^-3rad s^-1

B. 0.25 x 10^-1rad s^-1

C. 5.00 x 10²rad s^-1

D. 2.50 x 10³rad s^-1

17

If a sound wave goes from a cold air region to a hot air region, its wavelength will

A. increase

B. decrease

C. decrease then increase

D. remain constant

18

The lowest note emitted by a stretched string has a frequency of 40Hz. How many overtones are there between 40hz and 180Hz?

A. 4

B. 3

C. 2

D. 1

19

A man stands 4m in front of a plane mirror. If the mirror is moved 1m towards the man, the distance between him and his new image is

A. 3m

B. 5m

C. 6m

D. 10m

20

The inside portion of part of a hollow metal sphere of diameter 20cm is polished. The portion will therefore form a

A. concave mirror of focal length 5cm

B. concave mirror of focal length 10cm

C. convex mirror of focal length 5cm

D. convex mirror of focal length 20cm