JAMB Physics Past Questions & Answers - Page 60

296.

A train has an initial velocity of 44m/s and an acceleration of -4m/s\(^2\). Calculate its velocity after 10 seconds

A.

10m/s

B.

6m/s

C.

8m/s

D.

4m/s

Correct answer is D

V = u _ at, at u = 44m/s

44 + [-4]10

4m/s

297.

The value of T in the figure above is

A.

30N

B.

10.0N

C.

20N

D.

40N

Correct answer is D

Tsin30 + Tsin30 =40

2Tsin30 = 40

Tsin30 = 40/2 = 20

T(\(\frac{1}{2}\)) = 20

T = 20 x 2 = 40N

298.

According to kinetic molecular model, in gases

A.

The molecule are very fast apart & occupy all the space made available

B.

The particles occur in clusters with molecules slightly farther apart

C.

The particles vibrate about fixed positions and are held together by the strong intermolecular bond between them

D.

The particles are closely packed together, they occupy minimum space & are usually arranged in a regular pattern

Correct answer is A

In kinetic molecular model, gases are energized and thus moves freely, fast as they occupy specific space

299.

A metal rod has a length of 100cm at 200\(^oC\). At what temperature will its length be 99.4cm. If the linear expansivity of the material of the rod is 2 x 10\(^{-5}C^{-1}\)

A.

200\(^o\)C

B.

300\(^o\)C

C.

100\(^o\)C

D.

-100\(^o\)C

Correct answer is D

L\(_1\) = 100cm, T\(_1\) = 200\(^o\)C

L\(_2\) = 99.4cm,T\(_2\) = ?

\(\alpha\) = 2 x 10\(^{-5}\)C\(^{-1}\)

\(\alpha\) = \(\frac{L_2 - L_1}{L_1(T_2 - T_1)}\)

2 x 10\(^{-5} = \frac{99.4 - 100}{100( T_2 - 200)} = \frac{-0.6}{100(T_2 - 200)}\)

2 x 10\(^{-5}\) x \(100(T_2 - 200) = -0.6\)

\(T_2 - 200 = \frac{-0.6}{0.002} = - 300^oC\)

\(T_2 = 200 - 300 = -100^oC\)

 

 

 

300.

When blue and green colours of light are mixed, the resultant colour is

A.

cyan

B.

magenta

C.

black

D.

yellow

Correct answer is A

Cyan is a bluish-green colour