Question
Pointing to a boy in the picture, Manisha said, “His
fathers’s sister is the only daughter of my father’s father.” How is the boy’s father related to Manisha if the boy is not the real brother of Manisha?Solution
Only daughter of Manisha’s father’s father — Manisha’s paternal aunt. So, the boy’s paternal aunt is Manisha’s paternal aunt.  Thus, the boy’s father is Manisha’s uncle. Â
Match the following machines with their working principles:
(i) Electric motor -Â (a) Heat energy into mechanical energy
(ii) Steam engin...
A cube of side a encloses a point charge q at its center. What is the electric flux through one of its faces?
A ray of light travels from glass (n=1.5) to air (n=1). For which angle of incidence will the ray just graze the surface (total internal reflection limit)?
Who laid the foundations of Quantum Theory?
An object moves towards a convex lens of focal length 20 cm with a velocity of 5 cm/s. When the object is at 30 cm from the lens, find the rate at which...
Which device is best suited for measuring the temperature inside metallurgical furnaces?

In a diatomic gas at ordinary temperatures, how many degrees of freedom contribute to internal energy?
In which type of motion does the velocity of a body vary with time?
Angle of friction and angle of repose are