Multiple Choice QuestionsIf the momentum of a body increases from 10 units to 25 units in 5 sec, then the force acting on it is
1 unit
2 units
3 units
4 units
Sound waves consist of 20 compressions and 20 rarefactions in 10m length. The wavelength of the waves is
25cm
50cm
75cm
100cm
In which of the following cases of motion, are the distance moved and the magnitude of displacement equal?
A car moving in a circular path
A pendulum oscillating to and fro
The Earth revolving around the Sun
A car moving on a straight road
LED and CFL are very commonly used as sources of light in homes. Which of the following statements is true?
LED is better because CFL contains toxic materials
Both are equally good
Neither of them is good because both contain toxic materials
CFL is better because LED contains toxic materials
If the pressure over a liquid increases, its boiling point
increases
does not change
first decreases and then increase
decreases
A feather weighing 5 g and a nail weighing 10 g have the same kinetic energy. Which of the following statements is true about the momentum of the two bodies?
The heavier body will have higher momentum
Both will have equal momentum
It is not possible to compare the momentum of two objects
The lighter body will have higher momentum
Most Boards of Education have banned the dissection of animals because
procuring animals has become an expensive proposition
there is a need to sensitise students to prevention of cruelty to animals
they may spread new diseases
animals are no longer available for dissection
If the frequency of vibrations of a body is decreased and its amplitude is increased, then
pitch increases but loudness decreases
pitch decreases but loudness increases
both pitch and loudness of sound produced will increase.
both pitch and loudness of sound produced will decrease
B.
pitch decreases but loudness increases
The pitch of the sound is the characteristic which distinguishes between a shrill (or sharp) sound and a grave ( or flat) sound. It depends upon the frequency. A sound of high pitch is said to be shrill and its frequency is high. A sound of low pitch is said to be grave and its frequency is low. So, we say that if the frequency of vibrations of a body is decreased, pitch will decrease. The loudness that we sense is related to the intensity of sound. Intensity of sound is proportional to the square of amplitude and square of the frequency, but loudness is basically calculated by amplitude. So, the amplitude is increased, loudness increases.
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