1. Which is the incorrect formula for a body accelerating uniformly?
- A. a = v2 − \(\frac{u^2}{2}\)
- B. v2 = u2 + 2as
- C. s = ut + \(\frac{1}{2}\) at2
- D. v2 − u2= 2as
Correct Option: Answer is A
2. Which of the following is not an electromagnetic radiation?
- A. x – ray
- B. Radio waves
- C. sunlight
- D. sound waves
Correct Option: Answer is D
Electromagnetic waves do not require any material medium, but sound waves is a mechanical wave that require a material medium
3. Calculate the electric field intensity between two plates of potential difference 6.5V when separated by a distance of 35cm.
- A. 18.57NC\(^{-1}\)
- B. 53.06N C\(^{-1}\)
- C. 2.28NC\(^{-1}\)
- D. 0.80NC\(^{-1}\)
Correct Option: Answer is A
Electric Field Intensity (E) = \(\frac{v}{d}\)
= \(\frac{\text{potential difference}}{\text{distance}}\)
= \(\frac{6.5v}{35cm}\)
= \(\frac{6.5}{35 \times 10^{- 2}}\)
= 18.57NC\(^{-1}\)
4. Why do soldiers march disorderly while crossing a bridge?
- A. To prevent resonance on the bridge
- B. To set the bridge into resonance
- C. To make the b ridge collapse
- D. To spread their weight evenly on the bridge
Correct Option: Answer is A
Soldiers march disorderly while crossing a bridge to prevent resonance because when soldiers march in orderly manner across a bridge, they generate a rhythmic oscillation of wave on the bridge and at a certain point, would start oscillation to the same rhym as that of the marching steps. This oscillation would reach a maximum peak when the bridge can no longer sustain its own strength and hence collapses. So for this reasons, soldier are ordered to march disorderly while crossing a bridge
5.
Calculate the upthrust on an object of volume 50cm3 which is immersed in liquid of density 103kgm-3 [g = 10ms-2]
- A. 0.8N
- B. 2.5N
- C. 0.5N
- D. 1.0N
Correct Option: Answer is C
Upthrust = change in weight
density = \(\frac{\text{mass}}{\text{volume}}\)
Mass of liquid displaced = Density of Liquid × Volume;
= \(10^{3} \times 50 \times 10^{−6}m^{3}\)
= 0.05kg
(Note that the volume of \(50cm^{3}\) was converted to \(m^{3}\) by multiplying by \(10^{6}\)) i.e \(50cm^{3} = 50 \times 10^{−6}m^{3}\)
Since mass displaced = 0.05kg
Upthrust = mg = 0.05 × 10
= 0.5N
6. Under what conditions are cathode rays produced in a discharge tube?
- A. High pressure and low voltage
- B. High pressure and high voltage
- C. Low pressure and low voltage
- D. Low pressure and high volatge
Correct Option: Answer is D
Cathode rays are produced in a discharge tube under Low pressure and high voltage
7. Under which of the following conditions is workdone
- A. A man supports a heavy food above his head with his hands
- B. A boy climbs onto a table
- C. A man pushes unto a table
- D. A woman holds a pot of water
Correct Option: Answer is B
For work to be done, distance must be involved because
workdone = force × distance
8. Calculate the specific latent heat of vaporization of steam of 1.13 x 106J of heat energy is required to convert 15kg of steam to water.
- A. 7.53 x 105 Jkg\(^{-1}\)
- B. 7.53 x 10-2Jkg\(^{-1}\)
- C. \(7.53 \times 10^{4}\)Jkg\(^{-1}\)
- D. 7.53 x 10-3Jkg\(^{-1}\)
Correct Option: Answer is C
Quantity of heat = mass(m) × specific latent heat (L)
Q = mL
L = \(\frac{Q}{m}\)
= \(\frac{1.13 \times 10^{6}}{15}\)
= \(7.53 \times 10^{4}\)Jkg\(^{-1}\)
9. A cell of internal resistance 2 π supplies current to a 6 π resistor. The efficiency of the cell is
- A. 12.0%
- B. 25.0%
- C. 33.3%
- D. 75.0%
Correct Option: Answer is C
Internal resistance determine the maximum current that can be supplied
Efficiency = r / R × 100
= 2 / 6 × 100
= 33.3%
10. Which of the following statements is NOT correct?
- A. Molecules of a liquid are stationary
- B. Brownian motion is an evidence of particle nature of matter
- C. Matter is made up of molecules
- D. The molecules of matter are in constant motion
Correct Option: Answer is A
Brownian motion is an evidence of particle nature of matter
matter is made up of molecules
The molecules of matter are in constant motion