1.
What is the speed of sound in steel approximately?
A
1500 m/s
B
343 m/s
C
6000 m/s
D
5000 m/s
View Answer
Correct Answer: C — 6000 m/s
Explanation:
The speed of sound in steel is approximately 6000 m/s.
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What is the speed of sound in steel approximately?
1500 m/s
343 m/s
6000 m/s
5000 m/s
Correct Answer: C — 6000 m/s
Explanation:
The speed of sound in steel is approximately 6000 m/s.
Why is the speed of sound in solids higher than in gases?
Particles in solids are closely packed
Solids are more rigid
Solids are more elastic
All of the mentioned
Correct Answer: D — All of the mentioned
Explanation:
Close particle packing, rigidity, and elasticity make sound travel faster in solids.
Which of the following is an example of infrasonic sound?
Whale sounds
Earthquake tremors
Bat communication
Human speech
Correct Answer: B — Earthquake tremors
Explanation:
Earthquake tremors produce infrasonic waves with frequencies below 20 Hz.
What principle is used in SONAR for navigation?
Reflection of sound
Diffraction of sound
Interference of sound
Refraction of sound
Correct Answer: A — Reflection of sound
Explanation:
SONAR uses the reflection of sound waves to detect underwater objects.
What happens to sound waves when they hit a hard surface?
They are refracted
They are diffracted
They are absorbed
They are reflected
Correct Answer: D — They are reflected
Explanation:
Sound waves reflect from hard surfaces.
What is the persistence of sound due to multiple reflections called?
Echo
Diffraction
Reverberation
Refraction
Correct Answer: C — Reverberation
Explanation:
Reverberation is caused by repeated reflections of sound.
When is an echo heard?
When sound is absorbed
When the reflected sound reaches after 1/10th of a second
When the source of the sound is moving
When the sound is reflected
Correct Answer: B — When the reflected sound reaches after 1/10th of a second
Explanation:
An echo is heard when reflected sound reaches the listener after a noticeable time gap.
In which medium is the speed of sound the highest?
Solids
Gases
Liquids
Vacuum
Correct Answer: A — Solids
Explanation:
Sound travels fastest in solids because particles are closely packed.
Which of the following waves does not require a medium for propagation?
Sound
Seismic waves
Radio waves
Ocean waves
Correct Answer: C — Radio waves
Explanation:
Radio waves are electromagnetic waves and can travel through a vacuum.
Which of the following is a transverse wave?
Light waves
Sound waves in water
Waves in a slinky
Sound waves in air
Correct Answer: A — Light waves
Explanation:
Light waves are transverse electromagnetic waves.
Which of the following devices converts electrical energy to mechanical energy?
Battery
Fan
Heater
Solar panel
Correct Answer: B — Fan
Explanation:
A fan converts electrical energy into mechanical motion.
Which of the following affects the potential energy of an object?
Temperature of the object
Shape of the object
Height of the object
Speed of the object
Correct Answer: C — Height of the object
Explanation:
Gravitational potential energy depends on the height of an object.
A 75 kg man climbs a staircase with a height of 4 m. What is the work done against gravity?
300 J
750 J
3000 J
4000 J
Correct Answer: C — 3000 J
Explanation:
Work done = mgh = 75 × 10 × 4 = 3000 J.
What is 1 horsepower approximately equal to?
736 W
1000 W
746 W
10 W
Correct Answer: C — 746 W
Explanation:
One horsepower is approximately equal to 746 watts.
What happens to the total energy in a closed system?
It decreases
It remains constant
It increases
It becomes zero
Correct Answer: B — It remains constant
Explanation:
Total energy remains constant in a closed system according to the law of conservation of energy.
Which of the following is a high-power appliance?
Mobile phone charger
LED bulb
Refrigerator
Electric iron
Correct Answer: D — Electric iron
Explanation:
Electric irons consume a large amount of electrical power.
Which of the following is true about power?
It is the energy stored in an object
It is measured in newtons
It is the rate at which energy is used
It is inversely proportional to time
Correct Answer: C — It is the rate at which energy is used
Explanation:
Power is the rate at which work is done or energy is used.
What is the power required to do 100 J of work in 5 seconds?
200 W
50 W
10 W
20 W
Correct Answer: D — 20 W
Explanation:
Power = Work ÷ Time = 100 ÷ 5 = 20 W.
When a ball is thrown upward, its kinetic energy is converted into?
Electrical energy
Potential energy
Heat energy
Chemical energy
Correct Answer: B — Potential energy
Explanation:
As the ball rises, kinetic energy changes into potential energy.
The total energy of a body is the sum of which two forms of energy?
Work and energy
Heat and work
Kinetic and potential energy
Chemical and electrical energy
Correct Answer: C — Kinetic and potential energy
Explanation:
Mechanical energy is the sum of kinetic and potential energy.