JAMB Physics Past Questions & Answers - Page 69

341.

A solid cube of side 50cm and mass 75kg floats in a liquid with \(\frac{1}{3}\) of its height above the liquid surface. The relative density of the liquid is?

A.

0.33

B.

0.50

C.

0.67

D.

0.90

Correct answer is D

 = \(\frac{2}{3}\)(0.5)\(^3\)

  Mass of liquid displaced = mass of floating cube = 75kg

  Density of liquid = \(\frac{mass}{volume}\)

  = \(\frac{75}{(\frac{7}{3(0.5)})}\)  × 3

  = 0.9 × 103kgm\(^{-3}\)

  R.D of liquid = \(\frac{(0.9 )}{(1.0)}\) × 103

  = 0.9

342.

Which of the following concepts is not an evidence of the particles nature of matter?

A.

Diffusion

B.

Brownian motion

C.

Diffraction

D.

Esterification

Correct answer is D

Diffusion is the net movement of molecules/atoms from a region of high concentration to low concentration.

  Brownian motion is the erratic random movement of microscopic particles in a field.

  Diffraction is the various phenomena that occur when a wave encounters an obstacle.

343.

The product of force and time is?

A.

Impulse

B.

Momentum

C.

Inertia

D.

Friction

Correct answer is A

An impulse is equal to the net force on the object times the time period over which this force is applied. Impulse is derive from the equation F = ma, which comes from Newton's second law of motion

344.

Temperature is the property of a body which is proportional to the ____.

A.

total kinetic energy of its molecules

B.

average kinetic energy of its molecules

C.

average speed of its molecules

D.

maximum speed of its molecules

Correct answer is B

The last postulate of the kinetic molecular theory states that the average kinetic energy of a gas particle depends only on the temperature of the gas. Thus, the average kinetic energy of the gas particles increases as the gas becomes warmer

345.

What flows to the positively charged conductor by connecting it to the earth?

A.

Electrons

B.

Ion

C.

Neutron

D.

Proton

Correct answer is A

Earth acts as a ground of zero potential. So when a positively charged conductor is connected to the earth, positive charge flows into the earth and as a result, electrons flow from earth to the conductor.