Multiple choice question for engineering
1. What does conductivity of metals depend upon?
a) The nature of the material
b) Number of free electrons
c) Resistance of the metal
d) Number of electrons
2. The free electrons collide with the lattice elastically. True or false?
3. What happens to the free electrons when electric field is applied?
a) They move randomly and collide with each other
b) They move in the direction of the field
c) They remain stable
d) They move in the direction opposite to that of the field
4. Thermal conductivity is due to photons.
5. Which of the following theories cannot be explained by classical theory?
a) Electron theory
b) Lorentz theory
c) Photo-electric effect
d) Classical free electron theory
6. Which of the following theories can be adopted to rectify the drawbacks of classical theory?
a) Compton theory
b) Quantum theory
c) Band theory
d) Electron theory
7. What is the level that acts as a reference which separated the vacant and filled states at 0K?
a) Excited level
b) Ground level
c) Valance orbit
d) Fermi energy level
8. A uniform silver wire has a resistivity of 1.54×10-18 ohm/m at room temperature. For an electric field along the wire of 1 volt/cm. Compute the mobility, assuming that there are 5.8×1028 conduction electrons/m3.
a) 1.54 m2/Vs
c) 6.9973×10-3 m2/Vs
9. Calculate the drift velocity of the free electrons with mobility of 3.5×10-3 m2/Vs in copper for an electric field strength of 0.5 V/m.
a) 3.5 m/s
b) 1.75×103 m/s
c) 11.5 m/s
d) 1.75×10-3 m/s
10. The Fermi temperature of a metal is 24600K. Calculate the Fermi velocity.
1. Three different objects of masses m1, m2 and m3 are allowed to fall from rest and from the same point O along three different frictionless paths. The speeds of the three different objects on reaching the ground will be in the ratio of
2. A truck and a car are moving with equal velocity. On applying brakes, both will stop after certain distance, then
a) Truck will cover less distance before stopping
b) Car will cover less distance before stopping
c) Both will cover equal distance
d) None of the mentioned
3. If a ladder weighing 250N is placed against a smooth vertical wall having coefficient of friction between it and floor 0.3, then what is the maximum force of friction available at the point of contact between the ladder and the floor
4. A body of mass 2kg begins to slide down a plane inclined at an angle of 45° with the horizontal. The force of friction will be
a) 19.6sin 45°
b) 9.8sin 45°
c) 19.6cos 45°
d) 9.8cos 45°
5. A person sitting in an open car moving at constant velocity throws a ball vertically into air, the balls falls
a) Exactly in the hand of thrower
b) Outside the car
c) In the car ahead of the person
d) In the car behind the person
6. A stone of mass m tied to one end of string of length l is rotated in a circle with the other end of the string as the centre. The speed of the stone is v. If the string breaks, the stone will
a) Move towards the centre
b) Move away from the centre
c) Move along tangent
7. Two racing cars of masses m1 and m2 are moving in circle of radii r1 and r2 respectively. Heir speeds are such that each car makes a complete circle in same time t. The ratio of the angular speed of the first to the second car is
d) m1 m2:r1 r2
8. A man weighs 80kg. He stands on a weighing scale in a lift which is moving upwards with a uniform acceleration of 5m/s2. What would be the reading on the scale?
9. Consider a car moving along a straight horizontal road with a speed of 72km/h. If the coefficient of static friction between the tyres and the road is 0.5, the shortest distance in which the car can be stopped is (g=10m/s2)
10. A boy of 50kg is standing in a lift moving down with an acceleration 9.8m/s2. The apparent weight of the boy is
1. Assertion: In pressure-temperature phase diagram of water, the slope of the melting curve is found to be negative [Reason:] Ice contracts on melting to water
a) Both assertion and reason are true and reason is the correct explanation of the assertion
b) Both assertion and reason are true but reason is not correct explanation of the assertion
c) Assertion it true but reason is false
d) Both assertion and reason are false
2. At constant volume temperature is increases, then
a) Collisions on walls will be less
b) Number of collisions per unit time will increase
c) Collisions will be in straight line
d) Collisions will not change
3. Gases at low temperature and high pressure show large deviation from an ideal behaviour. True or false?
4. When an automobile travels for a long distance, the pressure in the gas
a) Increases slightly
b) Decreases slightly
c) Remains the same
d) Decreases and then increases
5. A vessel contains one mole of O2 gas at a temperature T. The pressure of the gas is P. An identical vessel containing one hole of He gas at a temperature 2T has a pressure of
6. The average translational kinetic energy of O2 molecules (relative molar mass 32) at a particular temperature is 0.048eV. The translational kinetic energy of N2 molecules (relative molar mass) in eV at the same temperature is
7. A gas mixture consists of 2 moles of oxygen and 4 moles of argon at temperature T. Neglecting all vibrational modes, the total internal energy of the system is
8. Surface the lake is at 2°C and depth of the lake is 20m. Find the temperature of the bottom of the lake
9. The degree of freedom in case of a monoatomic gas is
10. The mean kinetic energy of one mole of gas per degree of freedom (on the basis of kinetic theory of gases) is
a) (1/2) kT
b) (3/2) kT
c) (3/2) RT
d) (1/2) RT
1. In a vessel, the gas at a pressure P. If the mass of all molecules is halved and their speed is doubled, then the resultant pressure will be
2. The absolute zero is the temperature, at which
a) All substances exist in solid state
b) Water freezes
c) Molecular motion ceases
d) Solid melts
3. When we heat a gas-sample from 27°C to 327°C, then the initial average kinetic energy of the molecules was E. What will b the average kinetic energy?
4. Temperature less than absolute zero is not possible. True or false?
5. A given quantity of an ideal gas at pressure P and absolute temperature T. The isothermal bulk modulus of the gas is
a) 2/3 P
c) 3/2 P
6. Statement: The ration Cp/Cv is more for helium gas than that for hydrogen gas [Reason:] Atomic mass of helium is more than that of hydrogen
a) Both statement and reason are true and reason is the correct explanation of the statement
b) Both statement and reason are true but reason is not correct explanation of the statement
c) Statement it true but reason is false
d) Both statement and reason are false
7. The relation PV=RT can describe behaviour of the real gas at
a) High temperature and high density
b) High temperature and low density
c) Low temperature and low density
d) Low temperature and high density
8. An absolute zero is the temperature at which
a) Water solidifies
b) All gases become liquid
c) rms velocity becomes zero
d) Solids melt
9. The temperature of a given mass is increased from 27°C to 327°C. The rms velocity of the molecules increases
a) √2 times
b) 2 times
c) 2√2 times
d) 4 times
10. The ratio of the vapour densities of two gases at a given temperature is 9:8. The ratio of the rms velocities of their molecules is
1. Statement 1- The length of the day is slowly increasing
Statement 2- The dominant effect causing a slow down in the rotation of the earth is the gravitational pull of other planets in the solar system.
a) Statement 1 and statement 2 are correct and statement 2 is the correct explanation of statement 1
b) Statement 1 and statement 2 are correct but statement 2 is not the correct explanation of statement 1
c) Statement 1 is true but statement 2 is false
d) Both statement 1 and 2 are false
2. If the earth stops rotating, the value of g at the equator
c) No effect
d) First increases and then decreases
3. A satellite revolves very near to the earth surface. Its speed should be around
4. The value of escape velocity on a certain planet is 2km/s. Then the value of orbital speed for a satellite orbiting close to its surface is
5. If gravitational constant is decreasing with time, what will remain unchanged in case of a satellite orbiting around the earth?
a) Time period
b) Orbiting radius
c) Areal velocity
d) Angular velocity
6. An elephant and an ant are to be projected out of earth into space. What is the velocity needed to do so?
a) Elephant needs to be projected with a higher velocity
b) Ant should be projected with a higher velocity
c) Both should be projected with the same velocity
d) Elephant cannot be projected to space
7. An astronaut, while revolving in a circular orbit happens to throw a spoon outside. What will happen to the spoon?
a) It will reach the earth surface
b) It will escape the universe
c) It will remain stationary
d) It will continue to move in a circular orbit
8. It is possible to place an artificial satellite in an orbit, such that it is always visible over New Delhi. True or false?
9. A satellite does not need ant fuel to circle around the earth. True or false?
10. A satellite orbiting the earth with speed v0. To make the satellite escape, what should be the minimum percentage increase in its velocity?