Multiple choice question for engineering
1. The displacement of a particle varies according to the relation
The amplitude of the particle is
2. The displacement y of a particle in a medium can be expressed as
Where t is in seconds and x in meter. The speed of the wave is
3. The displacement y of a wave travelling in the x direction is given by
Where x is expressed in meters and t is seconds. The speed of the wave motion (in m/s) is
4. A wave y=asin(ωt-kx), on a string meets with another wave producing a node at x = 0. Then, the equation of the unknown wave is
5. The speed of sound in oxygen (O2) at a certain temperature is 460m/s. The speed of sound in helium (He) at the same temperature will be (assume both gases to be ideal)
6. Length of a string tied to two rigid supports is 40cm. Maximum length (wavelength in cm) of a stationary wave produced on it is
7. A metal wire of linear mass density of 9.8/gm is stretched with a tension of 10kg wt between two rigid supports 1m apart. The wire passes at its middle point between the poles of a permanent magnet and it vibrates in resonance, when carrying an alternating current of frequency v. The frequency v of the alternating source is
a) 50 Hz
b) 100 Hz
c) 200 Hz
d) 25 Hz
8. A sound absorber attenuates the sound level by 20dB. The intensity decreases by a factor of
9. The ratio of velocity of sound in hydrogen and oxygen at STP is
10. It takes 2 seconds for a second wave to travel between two fixed points when the day temperature is 10°C. If the temperature rises to 30°C, the sound wave travels between the same fixed parts in
a) 1.9 sec
b) 2 sec
c) 2.1 sec
d) 2.2 sec
1. Which of the following effects can be used to produce ultrasonic waves?
a) Magnetostriction effect
b) Doppler Effect
c) Magnetic effect
d) Sound effect
2. It is not possible to get a constant single frequency using magnetostriction effect. True or false?
3. When is ultrasonic waves produced using piezo electric oscillator?
a) At constant temperature
b) At resonance
c) At constant pressure
d) At constant voltage
4. Which of the following causes acoustical grating?
a) Magnetic waves
b) Electric waves
c) Magnetostriction effect
d) Ultrasonic waves
5. What is the principle for measurement of velocity of ultrasonic waves?
a) Magnetostriction effect
b) Acoustical grating
c) Doppler Effect
d) Acceleration effect
6. What is cold welding?
a) Welding at very low temperature
b) Welding using ultrasonic waves
c) Welding under water
d) Welding at constant temperature
7. What is the other name for ultrasonic flaw detector?
a) Destructive testing
b) Magnetostrictive testing
c) Non-destructive testing
d) Echo testing
8. Sonograms work under the principle of Doppler Effect. True or false?
9. A quartz crystal of thickness 0.001m is vibrating at resonance. Calculate the fundamental frequency. Density of quartz = 2.650×103 kg/m3 and Young’s modulus for quartz = 7.9×1010 N/m2.
10. An ultrasound pulse sent by a source in sea is reflected by a submerged target at a distance 597.50m and reaches the source after 0.83seconds. Find the velocity of sound in sea water.
1. If the density of planet is doubled without any change in its radius, how does g change on the planet?
a) It remains the same
b) It is tripled
c) It reduces
d) It is doubled
2. A body can be shielded from gravitational effects. True or false?
3. Gravity acts on all bodies in proportion to their masses; therefore heavy body falls faster than light body.
4. The mass of the moon is nearly 10% of the mass of the earth. What will be the gravitational force of the earth on the moon, in comparison to the gravitational force of the moon on the earth?
a) Both of the force will be equal
b) Gravitational force of the earth on the moon is much lesser
c) Gravitational force of the moon on the earth is much lesser
d) There is no effect
5. A man waves his arm, while walking. This is
a) To keep constant velocity
b) To ease the tension
c) To increase the velocity
d) To balance the effect of earth’s gravity
6. Kepler’s second law is based on
a) Newton’s first law
b) Newton’s second law
c) Special theory of relativity
d) Conservation of angular momentum
7. Statement 1- An astronaut experiences weightlessness in a space satellite
Statement 2- When a body falls freely, it does not experience gravity
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
8. Two spheres of masses m and M are in air and the gravitational force between them is F. The space around the masses is now filled with liquid of specific gravity 3. The gravitational force will now be
9. For a satellite escape velocity from earth is 11.2 km/s. If a body is to be projected in a direction making an angle 45° to the vertical, then the escape velocity is
10. If earth loses its gravity, then for a body
a) A weight becomes zero, but not the mass
b) Mass becomes zero but not weight
c) Neither mass nor weight becomes zero
d) Both mass and weight are zero
11. A ball is dropped from a spacecraft revolving around the earth at a height of 120km. What will happen to the ball?
a) It will go very far in space
b) It will move with the same speed tangentially to the spacecraft
c) It will fall down to the earth gradually
d) It will continue to move with the same speed along the original orbit of spacecraft
1. Which of the following is a metallic glass?
2. How are metallic glasses formed?
a) By increasing the rate of heating
b) By increasing the rate of cooling
c) By melting it
d) By rapidly heating and then cooling slowly
3. When does metal transform into glass?
a) At Curie temperature
b) At critical temperature
c) At melting point of the metal
d) At glass transition temperature
4. Which of the following is the most commonly used technique for preparation of metallic glass?
a) Melt spinning system
b) Twin roller system
c) Melt extraction system
5. Quenching results in formation of metallic glasses. True or false?
6. Which of the following is true about metallic glasses?
a) Low electrical resistance
b) Hexagonal closely packed structure
d) Low core loss
7. Metallic glasses cannot be use in cores of high power transformers. True or false?
8. When does a shape memory alloy return to its original shape?
a) At transition temperature
b) At Curie temperature
c) At memory transfer temperature
d) At normal temperature
9. Why is NI-Ti alloy used in making eye frames?
a) Because they are hard
b) Because they are not flexible
c) Because they are hard to break
d) Because they are SMA
10. Can SMA be used to control and prevent fire?
11. Which of the following can be used to prepare nano-powder and nano-particles?
a) Sol-gel technique
b) Plasma arching
c) Chemical vapour deposition
d) Electro deposition
1. A gun fires a bullet of mass 50g with a velocity of 30m/s. Because of this, the gun is pushed back with a velocity of 1m/s. The mass of the gun is
2. A body of mass 5kg is raised vertically to a eight of 10m by a force of 170N. The velocity of the body at this height will be
3. A position dependent force, F = 7-2x+3x2-N acts on a small body of mass 2kg and displaces it from x = 0 to x = 5m. The work done in joules is
4. A particle of mass M is moving in a horizontal circle of radius R with uniform speed v. When it moves from one point to a diametrically opposite point, its
a) Kinetic energy changes by (Mv)2/4
b) Momentum does not change
c) Momentum changes by 2Mv
d) Kinetic energy changes by (Mv)2
5. Two identical balls A and B collide head on elastically. If velocities of A and B, before the collision are +0.5m/s and -0.3m/s respectively, then the velocities after the collision, are
a) -0.5m/s and +0.3m/s
b) +0.5m/s and +0.3m/s
c) +0.3m/s and -0.5m/s
d) -0.3m/s and +0.5m/s
6. The kinetic energy acquires by a mass m in travelling distance d, starting from rest, under the action of a constant force is directly proportional to
7. A simple pendulum hanging freely and at rest is vertical because in that position
a) Kinetic energy is zero
b) Potential energy is zero
c) Kinetic energy is minimum
d) Potential energy is minimum
8. A bullet is fired and gets embedded in a block kept on table. If table is frictionless, then
a) Kinetic energy gets conserved
b) Potential energy gets conserved
c) Momentum gets conserved
d) Kinetic energy and potential energy gets conserved
9. A ball moves in a frictionless inclined table without slipping. The work done by the table surface on the ball is
10. Assertion: When a body moves along a circular path, no work is done by the centripetal force [Reason:] The centripetal force is used on moving the body along the circular path and hence no work is done
a) Both assertion and reason are true and reason is the correct explanation of the assertion
b) Both assertion and reason are true but the reason is not the correct explanation of assertion
c) Assertion is true but reason is false
d) Both assertion and reason are false