An object is placed at a distance of $$12 \mathrm{~cm}$$ from a convex lens on its principal axis and a virtual image of certain size is formed. If the object is moved $$4 \mathrm{~cm}$$ away from the lens, a real image of the same size as that of the virtual image is formed. The focal length of the lens in $$\mathrm{cm}$$ is
The graph of an object moving with speed v for a time t is shown below.
The graph that shows the distance s travelled by the same object for a time t is




An object of mass $$1 \mathrm{~kg}$$ is allowed to hang tangentially from the rim of the wheel of radius R. When released from the rest, the block falls vertically through $$4 \mathrm{~m}$$ height in 2 seconds. The moment of inertia is $$1 \mathrm{~kg} \mathrm{~m}^2$$. The radius of the wheel $$\mathrm{R}$$ is
A planet has double the mass of the earth and double the radius. The gravitational potential at the surface of the Earth is $$\mathrm{V}$$ and the magnitude of the gravitational field strength is $$\mathrm{g}$$. The gravitational potential and gravitational field strength on the surface of the planet are
Potential | Field | |
---|---|---|
A | V | $$\frac{g}{4}$$ |
B | 2V | $$\frac{g}{2}$$ |
C | V | $$\frac{g}{2}$$ |
D | 2V | $$\frac{g}{4}$$ |