Physics Past Questions And Answers
An open-tube mercury manometer is used to measure the pressure in a gas tank. When the atmospheric pressure is 101,325 Pa, what is the absolute pressure in Pa in the tank if the height of the mercury in the open tube is 25 cm higher
- A. 108,986 Pa
- B. 165,238 Pa
- C. 122,364 Pa
- D. 134,645 Pa
The space between the double glass walls of a thermos flask is evacuated space are silvered. The residual source of heat loss takes place by
- A. convection
- B. radiation from the surface
- C. conduction through the stopper and the glass
- D. conduction across the walls
A gas has a volume of 100cm3 at 27oC. If it is heated to temperature T until a final volume of 120cm3 is attained, calculate T
- A. 33oC
- B. 60oC
- C. 87oC
- D. 114oC
A body of mass 25kg, moving at 3ms-1 on a rough horizontal floor is at rest after sliding through a distance of 2.50m on the floor. Calculate the co-efficient of sliding friction. [g = 10.0ms-2]
- A. 0.09
- B. 0.18
- C. 0.36
- D. 0.54
The refractive index of a medium relative to air is 1.8. Calculate to the nearest degree, the critical angle for the medium
- A. 68°
- B. 56°
- C. 34°
- D. 18°
If light with photon energy 2eV is incident suitably on the surface of a metal with work function 3eV, then
- A. no electron will be emitted
- B. the few electrons emitted will have a maximum kinetic energy of 1eV
- C. the few electrons emitted will have a maximum kinetic energy of 3eV
- D. many electrons will be emitted
The inside portion of part of a hollow metal sphere of diameter 20cm is polished. The portion will therefore form a
- A. concave mirror of focal length 5cm
- B. concave mirror of focal length 10cm
- C. convex mirror of focal length 5cm
- D. convex mirror of focal length 20cm
When a known standard resistor of 2\(\Omega\) is connected to the 0.0cm end of a meter bridge, the balance point is found to be at 55.0cm. What is the value of the unknown resistor?
- A. 1.10\(\Omega\)
- B. 1.64\(\Omega\)
- C. 2.44\(\Omega\)
- D. 27.50\(\Omega\)
An object is placed 20cm from a lens. If an image is formed on a screen 260cm away from the lens, calculate the magnification of the image
- A. 28
- B. 26
- C. 24
- D. 13
The net capacitance in the circuit below is
- A. 80µF
- B. 6.0µF
- C. 4.0µF
- D. 2.0µF