In an experiment to measure the height of a bridge by dropping stone into water underneath. If the error in measurement of time is $$0.2 \mathrm{~s}$$ at the end of $$4 \mathrm{~s}$$, then the error in estimation of height of bridge will be (neglect the water resistance, i.e. thrust)
A conductor lies along the z-axis at $$-1.5 \leq Z \leq 1.5 \mathrm{~m}$$ and carries a fixed current of 10.0 $$\mathrm{A}$$ in $$-a_z$$ direction as shown in figure for a field $$B=3 \times 10^{-4} e^{-0.2 x} a_y \mathrm{~T}$$, the total power required to move the conductor at constant speed to $$x=2.0 \mathrm{~m}, y=0 \mathrm{~m}$$ in $$5 \times 10^{-3} \mathrm{~s}$$ is (Assume parallel motion along the $$x$$-axis)
A lens of refractive index $$\mu$$ is put in a liquid of refractive index $$\mu^{\prime}$$. If the focal length of lens in air is $$f$$, then its focal length in liquid will be
A parallel plate capacitor has an electric field of $$10^5 \mathrm{~Vm}^{-1}$$ between the plates. If the charge on the capacitor plates is $$1 \mu \mathrm{C}$$, the force on each capacitor plate is