Physics Past Questions And Answers
In an electrolysis experiment, the ammeter records a steady current of 1 A. The mass of copper deposited in 30 minutes is 0.66 g. Calculate the error in the ammeter reading. [Electrochemical equivalent of copper = 0.00033 g C\(^{-1}\)]
A moving-coil galvanometer which gives a full-scale on deflection with 0.005A is converted to a voltmeter reading up to 5V using an external resistance of 975Ω. What is the resistance of the metre?
- A. 0.25Ω
- B. 2.50Ω
- C. 25.00Ω
- D. 250.00Ω
In which of the following activities is an induction coil not useful?
- A. Investigation of high voltages
- B. Study of electric discharge
- C. Operation of X-ray tubes
- D. A.C. power transmission
A relative density bottle has a mass of 19 g when empty. When it is completely filled with water, its mass is 66 g. What will be its mass if completely filled with alcohol of relative density 0.8?
- A. 47 g
- B. 52.8 g
- C. 37.6 g
- D. 56.6 g
A boy drags a bag of rice along a smooth horizontal floor with a force of 2N applied at the angle of 60o to the floor. The work done after a distance of 3m is
- A) 3 J
- B) 4 J
- C) 5 J
- D) 6 J
Write down the name of:
(a) two particles used in explaining the wave nature of matter;
(b) one device whose invention is based on the wave nature of matter.
The term torque means
- A. the moment
- B. the resultant of several forces acting on a body in equilibrium
- C. two equal and oposite forces whose lines of action do not coincide
- D. two coplaner forces at right angles to each other
In an experiment to determine Young's Modulus for a wire, several loads are attached to the wire and the corresponding extension measured. The tensile stress in each case depends on the
- A. load and the extension
- B. load and the radius of the wire
- C. radius of the wire and the extension
- D. extension and the original length of the wire
State three properties of lasers that make them preferable to ordinary light beam.
Which of the following may be used to explain a mirage? I. Layers of air near the road surface have varying refractive indices in hot weather II. Road surfaces sometimes becomes invisible in hot weather III. Light from the sky can be refracted upwards after coming close to the road surface.
- A. I and III only
- B. II and III only
- C. II only
- D. I, II and III