## St. Xavier BASED PRACTICE MODEL QUESTION

### Physics

• The energy of charged capacitor increases by 21 % when additional charge 2C is added to its plate. The charge on the capacitor previously is:
1. 10 C
2. 15 C
3. 20 C
4. 25 C

• The power of a lamp is 40W at certain ac voltage. If the supply voltage is halved, the power would be
1. 40 W
2. 20 W
3. 10 W
4. 80 W

• A small circular flexible loop of wire of radius r carries a current I. It is placed in a uniform magnetic field B. The tension in the loop will be doubled if :
1. I is doubled
2. B is halved
3. r is doubled
4. both B and I are doubled

• A voltmeter has resistance of 2000𝞨 and it can measure upto 2V. If we want to increase its range by 8V, then required resistance in series will be
1. 4000𝞨
2. 6000𝞨
3. 7000𝞨
4. 8000𝞨

• The resistance of discharge tube is
1. zero
2. ohmic
3. non – ohmic
4. depends upon pressure

• Which of the following transitions in a hydrogen spectrum emits photons of the highest frequency
1. n = 1 to n = 2
2. n = 2 to n = 1
3. n = 2 to n = 2
4. n = 6 to n = 2

• Hydrogen atom does not produce x-rays because
1. its energy levels are too close to each other
2. its energy levels are too far apart
3. it is too small in size
4. it has a single electron

• If the forward voltage in a semiconductor diode is doubled, the width of depletion layer:
1. increases
2. decreases
3. remains unchanged
4. becomes zero
• For full wave rectification, the minimum number of diodes used is
1. 1
2. 2
3. 3
4. 4
• Two photons approach each other. Their relative velocity will be
1. 2c
2. c
3. c /2
4. zero
• When the length of a compound microscope tube increases, its magnifying power :
1. decreases
2. Increases
3. does not change
4. may increase or decreases
• Neutral temperature of a thermocouple is 320°C. The cold junction is at 10°C. The inversion temperature is :
1. 320°C
2. 630°C
3. 640°C
4. 650°C
• The maximum horizontal range of a projection is 400 m. The maximum height attained by it will be:
1. 100 m
2. 200 m
3. 400 m
4. 800 m
• If the momentum of a body is doubled, the kinetic energy is:
1. halved
2. unchanged
3. doubled
4. increase 4 times
• The dimensional formula of angular momentum is:
1. [ML2T-2]
2. [ML-2T-2]
3. [ML2T-1]
4. [ML-2T1]