22 + Interview Questions in TRANSIENT-CURRENT IN GENERAL AWARENESS Page 1 InterviewSolution

1.	Calculate the rms velocity of molecules of a gas of density `1.5 g litre^(-1)` at a pressure of `2 xx 10^(6) N//m^(2)`.
Answer» Correct Answer - `2 xx 10^(3) ms^(-1)`

Discussion

2.	The density of carbon dioxide gas at `0^(@)C` and at pressure `1.0 xx 10^(5) Nm^(-2)` is `1.98 kg m^(-3)`. Find the rms velocity of its molecules at `0^(@)C` and also at `30^(@)C`, assuming pressure to be constant.
Answer» Correct Answer - `389 ms^(-1), 410 ms^(-1)`

Discussion

3.	Calculate the rms velocity of `CO_(2)` molecules at N.T.P. Given `R = 8.31 K "mole"^(-1)K^(-1)`.
Answer» Correct Answer - `393.3 ms^(-1)`

Discussion

4.	The root mean square velocity of helium atoms at normal temperature and pressure is `1300 ms^(-1)`. Calculate (i) density of helium at `0^(@)C` and (ii) mass of helium atom. Normal pressure `= 1.01 xx 10^(5)Nm^(-2)`.
Answer» Correct Answer - (i) `0.179 kgm^(-3)`, (ii) `6.64 xx 10^(-27) kg`

Discussion

5.	Find the molecular kinetic energy of 1 g of helium at S.T.P. Given `R = 8.3 xx 10^(7) erg`.
Answer» Correct Answer - `8.5 xx 10^(9) erg`

Discussion

6.	A resistor R and `2muF` capacitor in series are connected to a 220V dc supply. Across the capacitor is a neon bulb that strikes at 120V. Calculate the value of R to make the bulb strike 5s after the switch has been closed.
Answer» Correct Answer - `2.73 MOmega`

Discussion

7.	A bulb contains air at atmospheric pressure at `40^(@)C`. The maximum pressure bulb can with stand is `2` atmosphere. Calculate of air when the bulb is on the point of bursting.
Answer» Correct Answer - `616 K`

Discussion

8.	What resistance must be connected in series with an inductor of 5mH so that the circuit has a time constant of `2 xx 10^(-3)S` ?
Answer» Correct Answer - `2.5Omega`

Discussion

9.	A capacitor of `1.443 muF` capacitance after being charged is shunted by a high resistance. If half the charge leaks away in one minute, find the value of the resistance.
Answer» Correct Answer - `59.99 M Omega`

Discussion

10.	A mass of gas exerts a pressure of `72 cm` of Hg at `27^(@)C`. It is heated at constant volume so that its pressure after some time is `90 cm` of Hg. Calculate the new temperature of the gas.
Answer» Correct Answer - `102^(@)C`

Discussion

11.	Calculate the number of molecules in each cubic metre of a gas at `1 atm` and `27^(@)C`.
Answer» Correct Answer - `2.45 xx 10^(25)`

Discussion

12.	A vessel of volume `2000cm^(3)` contains `0.1 mol` of oxygen and `0.2mol` of carbon dioxide. If the temperature if the mixture is `300K`, find its pressure.
Answer» Correct Answer - `3.74 xx 10^(5) Pa`

Discussion

13.	The mean kinetic energy of `1` kg-mol of nitrogen at `27^(@)C` is `600 J`. What will be its mean kinetic energy at `127^(@)C` ?
Answer» Correct Answer - `800 J`

Discussion

14.	A capacitor of `10muF` is connected with a resistance of `2.2 M Omega`. What is the time constant of the circuit.
Answer» Correct Answer - 22s

Discussion

15.	Consider hydrogen gas in a container at NTP. Calculate the average kinetic energy of each molecule.
Answer» Correct Answer - `5.65 xx 10^(-21)J`

Discussion

16.	A coil of resistance `11Omega` and inductance `0.1H` is connected to a 110V d.c. mains. Find (i) the current finally established in the coil. (ii) the voltage used in overcoming the resistance when the rising current is 3A, and (iii) the rate at which the current is rising at that instant.
Answer» Correct Answer - (i) 10A (ii) 33V (iii) `770 As^(-1)`

Discussion

17.	The temperature of a gas is `-68^(@)C`. To what temperature should it be heated so that (i) the average kinetic energy of the molecules be doubled and (ii) the root-mean-square velocity of the molecules be doubled ?
Answer» Correct Answer - (i) `137^(@)C` (ii) `547^(@)C`

Discussion

18.	A coil of inductance 10H and resistance `15Omega` is connected to a supply of 90V. Determine the value of current after 0.67s. How long will it take for the current to attain 50% of its final value ?
Answer» Correct Answer - `3.792A, 0.462s`

Discussion

19.	An open glass tube is immersed in mercury so that a length of `8 cm` of the tube projects above the mercury. The tube is then closed and raised through `44 cm`. What length of the tube will be occupied by the air after it has been raised? Given `1` atm `= 76 cm` of Hg.
Answer» Correct Answer - `15.4 cm`

Discussion

20.	A solenoid having a resistance of `5Omega` and self-inductance of 4H is connected to a battery of emf 10V and negligible resistance. After how long will the current in it rise to 1A ?
Answer» Correct Answer - 0.555s

Discussion

21.	A narrow uniform glass tube contains air enclosed by 15 cm long thread of mercury. When the tube is vertical with open end uppermost, the air column is 30 cm long. When the tube is inverted, the length of air column becomes 45 cm. Calculate the atmospheric pressure.
Answer» Correct Answer - `75` cm of Hg

Discussion

22.	Find the volume of `1g` of `CO_(2)` at `107^(@)C` and half the standard pressure when `1` ml of `CO_(2)` weighs `0.0019 g` at S.T.P.
Answer» Correct Answer - `1465.2 ml`

Discussion

Explore topic-wise InterviewSolutions in .

Calculate the rms velocity of molecules of a gas of density `1.5 g litre^(-1)` at a pressure of `2 xx 10^(6) N//m^(2)`.

The density of carbon dioxide gas at `0^(@)C` and at pressure `1.0 xx 10^(5) Nm^(-2)` is `1.98 kg m^(-3)`. Find the rms velocity of its molecules at `0^(@)C` and also at `30^(@)C`, assuming pressure to be constant.

Calculate the rms velocity of `CO_(2)` molecules at N.T.P. Given `R = 8.31 K "mole"^(-1)K^(-1)`.

The root mean square velocity of helium atoms at normal temperature and pressure is `1300 ms^(-1)`. Calculate (i) density of helium at `0^(@)C` and (ii) mass of helium atom. Normal pressure `= 1.01 xx 10^(5)Nm^(-2)`.

Find the molecular kinetic energy of 1 g of helium at S.T.P. Given `R = 8.3 xx 10^(7) erg`.

A resistor R and `2muF` capacitor in series are connected to a 220V dc supply. Across the capacitor is a neon bulb that strikes at 120V. Calculate the value of R to make the bulb strike 5s after the switch has been closed.

A bulb contains air at atmospheric pressure at `40^(@)C`. The maximum pressure bulb can with stand is `2` atmosphere. Calculate of air when the bulb is on the point of bursting.

What resistance must be connected in series with an inductor of 5mH so that the circuit has a time constant of `2 xx 10^(-3)S` ?

A capacitor of `1.443 muF` capacitance after being charged is shunted by a high resistance. If half the charge leaks away in one minute, find the value of the resistance.

A mass of gas exerts a pressure of `72 cm` of Hg at `27^(@)C`. It is heated at constant volume so that its pressure after some time is `90 cm` of Hg. Calculate the new temperature of the gas.

Calculate the number of molecules in each cubic metre of a gas at `1 atm` and `27^(@)C`.

A vessel of volume `2000cm^(3)` contains `0.1 mol` of oxygen and `0.2mol` of carbon dioxide. If the temperature if the mixture is `300K`, find its pressure.

The mean kinetic energy of `1` kg-mol of nitrogen at `27^(@)C` is `600 J`. What will be its mean kinetic energy at `127^(@)C` ?

A capacitor of `10muF` is connected with a resistance of `2.2 M Omega`. What is the time constant of the circuit.

Consider hydrogen gas in a container at NTP. Calculate the average kinetic energy of each molecule.

A coil of resistance `11Omega` and inductance `0.1H` is connected to a 110V d.c. mains. Find (i) the current finally established in the coil. (ii) the voltage used in overcoming the resistance when the rising current is 3A, and (iii) the rate at which the current is rising at that instant.

The temperature of a gas is `-68^(@)C`. To what temperature should it be heated so that (i) the average kinetic energy of the molecules be doubled and (ii) the root-mean-square velocity of the molecules be doubled ?

A coil of inductance 10H and resistance `15Omega` is connected to a supply of 90V. Determine the value of current after 0.67s. How long will it take for the current to attain 50% of its final value ?

An open glass tube is immersed in mercury so that a length of `8 cm` of the tube projects above the mercury. The tube is then closed and raised through `44 cm`. What length of the tube will be occupied by the air after it has been raised? Given `1` atm `= 76 cm` of Hg.

A solenoid having a resistance of `5Omega` and self-inductance of 4H is connected to a battery of emf 10V and negligible resistance. After how long will the current in it rise to 1A ?

A narrow uniform glass tube contains air enclosed by 15 cm long thread of mercury. When the tube is vertical with open end uppermost, the air column is 30 cm long. When the tube is inverted, the length of air column becomes 45 cm. Calculate the atmospheric pressure.

Find the volume of `1g` of `CO_(2)` at `107^(@)C` and half the standard pressure when `1` ml of `CO_(2)` weighs `0.0019 g` at S.T.P.