Answer:
D. The frequency is not affected as the volume of sound increases
Explanation:
Volume of the sound is defined by the amplitude of the wave or how loud a sound is whereas Frequency is basically the pitch of the sound and is inversely proportional to the wavelength . Increasing frequency will increase the pitch of the sound without affecting it's volume.
 
        
             
        
        
        
Due that the velocity is constant that means that friction force is equal to the force exert by you, otherwise the refrigerator will accelerate or decelerate and in both cases velocity will not be constant.  
So then the friction force between refrigerator and floor is 150 Newtons.
        
                    
             
        
        
        
Answer:
(a) T = 2987.6 k
(b) T = 19986.2 k 
Explanation:
The temperature of a star in terms of peak wavelength can be given by Wein's Displacement Law, which is as follows:

where,
T = Radiated surface temperature 
 = peak wavelength
 = peak wavelength
(a)
here,
 = 970 nm = 9.7 x 10⁻⁷ m
 = 970 nm = 9.7 x 10⁻⁷ m
Therefore,

<u>T = 2987.6 k</u>
(b)
here,
 = 145 nm = 1.45 x 10⁻⁷ m
 = 145 nm = 1.45 x 10⁻⁷ m
Therefore,

<u>T = 19986.2 k</u>
 
        
             
        
        
        
. In single particle problem whole mass is concentrated at a single point so it has a single displacement, single velocity and single acceleration. while, in rigid body mass is distributed
        
             
        
        
        
Answer:Ultraviolet radiation has shorter wavelengths and higher energy than infrared radiation.
Explanation: Electromagnetic radiation radiations which have both electrical and magnetic properties,they can be transmitted through space or through a medium.
It includes Gamma radiation, infra-red, visible light, Ultraviolet radiation etc they occur with different wavelength, the lower the wavelength the higher the Energy dissipated per photon. According to their order of decreasing wavelength and increased energy they are classified as follows.
RADIO WAVE, MICRO WAVE, INFRA-RED, VISIBLE LIGHT, ULTRAVIOLET RAY, X-RAY, GAMMA RAYS.