A man standing on a lift that is descending does not feel any weight because
- A. the inside of the lift is air tight
- B. the lift is in vacuum
- C. the lift's acceleration is same as acceleration due to gravity
- D. there is no gravitational pull on the man in the lift
Which of the following is a pure semiconductor?
- A. carbon
- B. silicon
- C. transistor
- D. phosphorus
Transistors are used for the?
- A. rectification of signals
- B. conversion of a.c to d.c
- C. amplification of signals
- D. conversion of d.c to a.c
The ground stated energy for the hydrogen atom is 5.44 x 10-19J . If an electron drops from zero energy to ground state, calculate the frequency of the emitted radiation?
[h = 6.6 x 10-34 Js]
- A. 5.0 x 1016 Hz
- B. 2.0 x 1016 Hz
- C. 5.0 x 1015 Hz
- D. 2.0 x 1015 Hz
- E. No correct option
In a discharge tube, most of the gas is pumped out so that electricity is conducted at?
- A. low voltage
- B. steady voltage
- C. high pressure
- D. low pressure
In alternating current circuit at resonance, the angle of lead or lag is?
- A. π°
- B. (π)/2°
- C. (π)/3°
- D. 0°
Two inductors of inductance 5 mll and 15 mll are connected in series and a current of 5A flows through them. the total energy stored in the inductor is?
- A. 500.0J
- B. 250.0J
- C. 62.5J
- D. 50.0J
- E. no correct option
A galvanometer with full-scale deflection of 10 mA is to be converted to a voltmeter with full-scale deflection of 5v. if a series resistance of 498Ω is used for the conversion, the resistance of the galvanometer is ?
- A. 1Ω
- B. 2Ω
- C. 5Ω
- D. 10Ω
Power supply is transmitted at a very high voltage and low current in order to?
- A. make pass through the trasformers
- B. increase the power supply
- C. make it travel fast
- D. prevent overheating of the coil
When a positively charged rod is brought nearer the cap of a positively charged electroscope, the leaves divergence will?
- A. be induced
- B. converge
- C. diverge
- D. remain constant
Dispersion occurs when white light passes through a glass prism because of the?
- A. different hidden colours in the glass
- B. different speeds of the colour in the glass
- C. defects in the glass
- D. high density of the glass
Which of the following is used for the correction of short sightedness?
- A. convex lens
- B. concave lens
- C. convex mirror
- D. concave mirror
The frequency of the wave in the diagram above is
- A. 0.17 Hz
- B. 0.25 Hz
- C. 1.57 Hz
- D. 1.05 Hz
A progressive wave equation is represented by y = a sin(150 πt – πx/4). if the phase difference of a progressive wave is 45°, the value of x in the equation is
- A. 3 cm
- B. 4 cm
- C. 1 cm
- D. 2 cm
An engine of a car of power 80 kW moves on a rough road with a velocity of 32 m\(s^-1\). The forces required to bring it to rest is
- A. 2.56 x 106N
- B. 2.50 x 106N
- C. 2.80 x 103N
- D. 2.50 x 103N
A shooter wants to fire a bullet in such a way that its horizontal range is equal to three times its maximum height. At the what angle should he fire the bullet to achieve this?
- A. 68o
- B. 53o
- C. 30o
- D. 45o
In a gas experiment, if the volume of the gas is plotted against the reciprocal of the pressure, the unit of the slope of the resulting curve is
- A. force
- B. temperature
- C. power
- D. work
A mirror of weight 75N is hung by a cord from a hook on the wall. If the cord makes an angle of 30o with horizontal, the tension in the cord is
- A. 100N
- B. 1500N
- C. 250N
- D. 150N
In the diagram above, the pressure of the gas is
- A. 86 cm of mercury
- B. 66 cm of mercury
- C. 96 cm of mercury
- D. 76 cm mercury
An object is embedded in a block of ice, 10 cm below the plane surface. if the refractive index of the ice is 1.50, the apparent depth below the surface is?
- A. 2.50 cm
- B. 6.67 cm
- C. 7.50 cm
- D. 7.63 cm
An object 4 cm high is placed 15 cm from a concave mirror of focal length 5 cm. The size of the image is?
- A. 2 cm
- B. 3 cm
- C. 4 cm
- D. 5 cm