JAMB Physics Past Questions & Answers - Page 61

301.

The graph of density against temperature for water is correctly illustrated by

A.

I

B.

II

C.

III

D.

IV

Correct answer is C

No explanation has been provided for this answer.

302.

According to Newton's law of cooling, the heat energy lost per unit area of a body depends on the

I. Surface area

II. Nature of the surface

III. Temperature of the surface

IV. Excess temperature over the surroundings

A.

I and II only

B.

II and IV only

C.

I,II and III

D.

I, II and IV

Correct answer is C

The rate of cooling of liduid according to Newton's law of cooling depends on:

- Temperature of the liquid

- Temperature of the enclosure

- The area of the exposed surface

- The nature and extent of the surface of the containing vessel

303.

A body is projected with an initial velocity u at angle \(\theta\) to the horizontal. If \(R_{max}\) is the maximum range of the projectile, what does the relation \(\frac{u^{2}}{R_{max}}\) represent?

A.

The vertical distance covered

B.

Acceleration due to gravity

C.

The horizontal distance covered

D.

The acceleration of the body

Correct answer is B

\(R_{max} = \frac{u^{2}}{g}\)

Hence, \(g = \frac{u^{2}}{R_{max}}\)

304.

Which of the following quantities are dimensionally independent?

I. Dielectric constant    II. Momentum   III. Efficiency   IV. Refractive index

A.

I and II

B.

II, III and IV

C.

I, II, III and IV

D.

I, III and IV

Correct answer is D

The quantities Efficiency, Dielectric constant and Refractive index are dimensionless.

305.

A block is acted upon by TWO horizontal forces as illustrated in the diagram above. The block accelerates at 1.5\(ms^{-2}\). Calculate the mass of the block.

A.

6kg

B.

9kg

C.

10kg

D.

15kg

Correct answer is A

Total force exerted on the block = (10 - 1)N =9N

Force = mass x acceleration

9 = m x 1.5

m = 9/1.5 = 6kg