The materials suitable for making electromagnets should have

A body falls on a surface of coefficient of restitution 0.6 from a height of $$1 \mathrm{~m}$$. Then the body rebounds to a height of

In a diffraction pattern due to single slit of width '$$a$$', the first minimum is observed at an angle of $$30^{\circ}$$ when the light of wavelength $$5400 \mathop A\limits^o$$ is incident on the slit. The first secondary maximum is observed at an angle of $$\left(\sin 30^{\circ}=\frac{1}{2}\right)$$

A stone is projected vertically upwards with speed '$$v$$'. Another stone of same mass is projected at an angle of $$60^{\circ}$$ with the vertical with the same speed '$$v$$'. The ratio of their potential energies at the highest points of their journey is $$\left[\sin 30^{\circ}=\cos 60^{\circ}=0.5, \cos 30^{\circ}=\sin 60^{\circ}=\frac{\sqrt{3}}{2}\right]$$