Answer:
F'= 4F/9
Explanation:
Two small objects each with a net charge of +Q exert a force of magnitude F on each other. If r is the distance between them, then the force is given by :
...(1)
Now, if one of the objects with another whose net charge is + 4Q is replaced and also the distance between +Q and +4Q charges is increased 3 times as far apart as they were. New force is given by :
.....(2)
Dividing equation (1) and (2), we get :

Hence, the correct option is (d) i.e. " 4F/9"
Answer:
300 Newtons
Explanation:
Weight is the force of attraction between two bodies, one usually larger (like a planet), and one smaller (like a person). Force can be calculated using the formula: Force = mass × acceleration.
The mass here is 12kg, the acceleration, which in this case, is the acceleration due to gravity is 25m/s/s, by plugging in our values, we have
Force = 12 × 25 = 300 Newtons or 300 N for short.
Answer:
Explanation:
Given


same charge on both masses
potential Energy due to Magnetic Field =Kinetic Energy of Particle


and we know
Force due to magnetic field will Provide centripetal Force


and B is equal for both particles
thus 



To solve this problem it is necessary to apply the concepts related to the principle of superposition and the equations of destructive and constructive interference.
Constructive interference can be defined as

Where
m= Any integer which represent the number of repetition of spectrum
= Wavelength
d = Distance between the slits.
= Angle between the difraccion paterns and the source of light
Re-arrange to find the distance between the slits we have,



Therefore the number of lines per millimeter would be given as



Therefore the number of the lines from the grating to the center of the diffraction pattern are 380lines per mm
Answer:
doppler effect
Explanation:
When the relative motion of two bodies results in the wavelength becoming shorter this means that the bodies are getting closer. This is known as blue shift.
When the relative motion of two bodies results in the wavelength becoming longer this means that the bodies are getting farther. This is known as red shift.
Collectively this phenomenon is known as the Doppler effect.