A man stands between two parallel cliffs (not in middle). When he claps his hands, he hears two echoes one after is and the other after $$2 \mathrm{~s}$$. If the velocity of sound in air is $$330 \mathrm{~m} / \mathrm{s}$$, the width of the cliff is
Light of wavelength $$\lambda$$ strikes a photoelectric surface and electrons are ejected with kinetic energy $$K$$. If $$K$$ is to be increased to exactly twice its original value, the wavelength must be changed to $$\lambda^{\prime}$$, such that
When in $$p$$-$$n$$ junction diode, $$p$$ is connected to the positive terminal and $$n$$ is connected to the negative terminal, then it is
If an object of height $$6 \mathrm{~cm}$$ is viewed through a liquid of refractive index $$\frac{4}{3}$$ vertically at a depth of $$10 \mathrm{~cm}$$. Then what will be its apparent height and apparent distance from the surface of liquid.