JAMB Physics Past Questions & Answers - Page 220

1,096.

An electric current of 3Aflowing through an electric heating elements of resistance 20 embedded in 1,000g of an oil raises the temperature of the oil by 10^oC in 10 seconds then the specific heat capacity of the oil is

1.8Jg^-1^oC

0.6Jg^-1^oC

0.18Jg^-1^oC

18Jg^-1^oC

0.06Jg^-1^oC

View answer & explanation

Correct answer is C

Heat energy = Electrical energy

mc\(\Omega\) = I²RTt

1000 x c x 10 = 3 x 3 x 20 x 10

0.18Jg^-1^oC

1,097.

If the normal atmospheric pressure in a laboratory supports a column of mercury 0.76m high and the relative density of mercury is 13.8, then the height of water column which atmospheric pressure will support in the same laboratory at the same time is

10m

13m

14m

18m

View answer & explanation

Correct answer is B

Density of H₂O = 1gcm³

Density x pressure = constant

D₁ x P₁ = D₂ x P₂

13.6 x 0.76 = 1 x P₂

P₂ = 10m

1,098.

A machine has a velocity ratio of 5. It requires a 50kg weight to overcome a 200kg weight. The efficiency is

40%

50%

80%

View answer & explanation

Correct answer is E

Efficiency = M.A x 100%

= \(\frac{200}{50}\) x \(\frac{1}{5}\) x 100

= 80%

1,099.

A short response to time is obtained in liquid-in-glass thermometer when the

bulb is large and thick-walled

stem is long and thin

bulb is small and thicked-walled

liquid is of high density and the bore is large

bulb is thin-walled and the liquid is a good conductor of heat

View answer & explanation

Correct answer is E

No explanation has been provided for this answer.

1,100.

Which of the following statements is CORRECT?

i. the mass number is equal to the total number of protons and electrons in an atom.
ii. the atomic number is equal to the number of protons in an atom.
iii. the number of electrons in an atom is equal to the total number of protons and neutrons in the nucleus.

i only

ii only

iii only

i and ii only

ii and iii only

View answer & explanation

Correct answer is B

No explanation has been provided for this answer.