Answer:
The correct answer is option 'd': The frequency decreases and the intensity of the sound decreases.
Explanation:
1) <u>Effect on Frequency </u>
According to Doppler's effect of sound we have
for a source of sound moving away from the observer the relation between the observed and the original frequency is given by
where
c = speed of sound in air
is the velocity of observer of sound
is the velocity of source of sound
is the original frequency of sound
As we see the ratio is less than 1 thus the frequency of sound that the observer receives is less than that of source.
2) <u>Effect on Intensity:</u>
At a distance 'r' from source emitting a wave of Power 'P' is given by
As we see on increasing 'r' intensity of sound decreases.
Answer : The rate of heat transfer to the water is, 37.92 kJ/min
Explanation : Given,
Time = 10 min
Mass of water = 200 g
Latent heat of fusion of water = 334 J/g
Latent heat of vaporization of water = 2230 J/g
Now we have to calculate the rate of heat transfer to the water.
Now put all the given values in the above formula, we get:
Thus, the rate of heat transfer to the water is, 37.92 kJ/min
Answer:
Resistivity of both wires are same
Explanation:
Length of one wire,
Diameter,
Radius,
Temperature in each case is same.
Area of each wire,
Resistivity is the property of material due to which it offers resistance to the flow of current.
Resistivity of material depends upon the temperature and material by which it is made.
It does not depends upon the length of object.
Therefore, the resistivity of both wires of different length are same.
<span>To find the wavelength of a neutron can be calculated by using the formula
Wavelength=h/m x v
Where h is planck's constant
m=mass of neutron
v= velocity of the particle
By substituting the given values
Wavelength= 6.63 × 10–34 j s / 1.675 × 10–27 kg x 2 m/s^-1
Wavelength of a neutron=1.979 x 10^-7 m</span>
Answer:
Explanation:
Since the roundabout is rotating with uniform velocity ,
input power = frictional power
frictional power = 2.5 kW
frictional torque x angular velocity = 2.5 kW
frictional torque x .47 = 2.5 kW
frictional torque = 2.5 / .47 kN .m
= 5.32 kN . m
= 5 kN.m
b )
When power is switched off , it will decelerate because of frictional torque .
