PHYSICS

 Any two masses in the universe attract each other with a force which is  i) directly proportional to the product of the masses, ii) inversely proportional to the square of the distance between their centres. F=GmM/r²  where G= universal gravitational constant. m and M are the masses of two bodies. r = distance between them.  * Larger the masses , greater is the force between them. * Larger the distance , smaller is the force. * If the distance is halved , force increases 4 times. * If the distance is doubled,  force becomes one-fourth. * The force is not effected with any medium between the masses. 

Q: What is the angle of deviation produced by a parallel glass slab? Ans: 0°. The incident ray is parallel to the emergent ray.

 Class 10                                                                     Marks: 20 Physics Revision ATTEMPT ALL QUESTIONS. Define moment of force. Write relationship between the SI and CGS unit of moment of couple. 2 Find the mass of the scale in equilibrium .                                          Draw diagrams and locate the centre of gravity  of hollow cone and triangular sheet. 2  State the  type of work done by a coolie  when i)  he lifts a load up ii) when he moves on a horizontal platform carrying load on his head.     2 A force is applied on a body of mass 20kg movong with a velocity of 40 m/s. The body attains a velocity of 50 m/s in 2  s. C...

 Red colour has longest wavelength so it has maximum speed in a medium compared to other colours.  As it travels with maximum speed in a medium,  the refractive index of the medium for Red colour is minimum.

Which is always constant for a machine of given design: MA or VR ? Ans: VR remains constant for a machine of given design as it depends on the distances moved by the load and effort but MA can vary due to the friction developed between the moving parts of the machine.

LENZ'S LAW is based on law of conservation of a) mass b) charge c) momentum  d) energy. Ans: d)   energy