Physics Past Questions And Answers
A substance has a half of 3mins. after 6mins. the count rate was observed to be 400. What was its count rate at zero time?
- A. 200
- B. 1200
- C. 1600
- D. 2400
A wire of length 10m is cooled from 50oC to 10oC. Calculate the decrease in the length of the wire. [c = 3 x 10-5K-1]
- A. 1.8 x 10-4m
- B. 1.5 x 10-4m
- C. 1.2 x 10-2m
- D. 1.8 x 10-3m
A car travelling with a uniform velocity of 30ms-1 along a horizontal road overcomes a constant frictional force of 600N. Calculate the power of the engine of the car
- A. 18kW
- B. 20kW
- C. 180kW
- D. 200kW
A simple machine with an efficiency of 75% lifts a load of 5000N when a force of 500N is applied to it. Calculate the velocity ratio of the machine
- A. 10.0
- B. 13.3
- C. 17.5
- D. 25.0
Which of the following statements is correct? When capacitors of different values are connected in series
- A. the same charge flows through them
- B. the same voltage appears across each capacitor
- C. different quantities of charges flow through them in different voltages across them
- D. different quantities of charges flows through them with the same voltage across them
The diagrams below illustrate electrical connections to the element of an electric pressing iron.In which of the connections is the fuse correctly fixed?
- A. I
- B. II
- C. III
- D. IV
A note of frequency of 2000Hz has a velocity of \(400ms^{-1}\). What is the wavelength of the note?
- A. 800m
- B. 200m
- C. 5m
- D. 0.2m
A solid of mass 0.5kg initially at 50oC melts at 60oC. Calculate the quantity of heat required to melt it completely. [specific heat capacity of the solid =2.0KJ kg-1K-1][Specific latent heat of fusion of solid =1.0 KJ kg-1]
- A. 1500J
- B. 10000J
- C. 10500J
- D. 15000J
Which of the following explains the concave meniscus of water in a clean glass tube? the
- A. adhension between water and glass molecules is greater than the sdhension between water molecules
- B. cohension between water molecules is greater then the adhension between glass and water molecule
- C. molecules of water near the glass move faster than the molecules at the centre of the tube
- D. molecules of water at the water-air boundary are often attracted to the centre of the tube
the core of a transformer is usually laminated in order to
- A. reduce magnetic leakage
- B. reduce eddy current
- C. prevent vibration of the transformer
- D. make magnetic reversal in the core much easier