Physics

A car is skidding on an icy road with speed $v$ and tyres are rotating with angular speed $\frac{v}{3R}$ , where $R$ is the radius of tyres. The distance travelled by car in one rotation of tyres is

Are AC generators better than DC generators?

A telescope with objective of focal length $100cm$ and eyepiece of focal length $5cm$ is focused on a far object such that parallel rays emerge from eyepiece. If object subtends an angle of $1^0$ on objective, the angular size of image is

Deviation of light ray by a thin prism of refractive index $\mu$ and refracting angle $A$  is

The radius of circle, the period of revolution $T$ , initial position and sense of revolution are indicated in the figure. x-projection of the radius vector of rotating particle $P$  is

What is the difference between slip ring and commutator?

Two conducting rods inclined at $\text{'}\theta \text{'}$ angle from horizontal are kept parallel at separation $\text{'}l\text{'}$ to each other. A resistor of resistance $R$ joins the two rods at their topmost point. A metal bar of length $\text{'}l\text{'}$ is free to slide on the rods as shown in figure. on releasing from rest, the maximum speed that can be attained by the bar if a constant magnetic field $B$ exists vertically downwards, is

What is the difference between AC and DC current?

Consider the following two statements .

(A)The gravitational force on a particle inside a spherical shell is zero.

(B) Total mechanical energy of a body on earth's surface may be positive.

Which of the following options is correct?

A man who can swim with a speed of $2kh/h$  wants to cross a river $200m$ wide. If the river is flowing with a speed of $3km/h$ then in what minimum time can the man cross the river?