NECO Physics Past Questions & Answers - Page 58

287.

A waterfall is 630cm high. What is the change in temperature of a quantity of water that falls from the top to the bottom of the waterfall? (Neglect heat losses to the surroundings, take g as 10 ms-2 and specific heat capacity of weather as 4200J kg-1K-1

A.

0.15°C

B.

1.50°C

C.

15.00°C

D.

21.00 °C

E.

50.00°C

Correct answer is B

water height as 630cm, gravity = 10m/s\(^2\),   specific heat capacity of weather as 4200J 

Temperature change = \(\frac{gh}{c}\) = \(\frac{630*10}{4200}\)

= 1.5C

288.

What is X in the equation given below? 42He + 94Be → 126C + X

A.

electron

B.

hydrogen

C.

lithium

D.

neutron

E.

proton

Correct answer is D

No explanation has been provided for this answer.

289.

Notes of the same frequency sounded on a piano and on a flute may differ in

I. pitch
II. quality
III. Loudness

A.

I only

B.

II only

C.

I and III only

D.

II and III only

E.

I, II and III

Correct answer is B

Quality is that characteristic note which distinguishes the two sounds of the same loudness and same pitch but emitted by two different instruments.

290.

What is the energy stored in a 10μ F capacitor if the potential difference between the plates is 40 V?

A.

2.0 × 10-4J

B.

8.0 ×10-4J

C.

4.0 × 10-3J

D.

8.0 × 10-3J

E.

1.6 × 10-2J

Correct answer is D

No explanation has been provided for this answer.