A proton and an alpha-particle moving with the same velocity enter a uniform magnetic field with their velocities perpendicular to the magnetic field. The ratio of radii of their circular paths is
A moving coil galvanometer is converted into an ammeter of range 0 to $$5 \mathrm{~mA}$$. The galvanometer resistance is $$90 \Omega$$ and the shunt resistance has a value of $$10 \Omega$$. If there are 50 divisions in the galvanometer-turned-ammeter on either sides of zero, its current sensitivity is
A square loop of side $$2 \mathrm{~cm}$$ enters a magnetic field with a constant speed of $$2 \mathrm{~cm} \mathrm{~s}^{-1}$$ as shown. The front edge enters the field at $$t=0 \mathrm{~s}$$. Which of the following graph correctly depicts the induced emf in the loop?
(Take clockwise direction positive)
In series $$L C R$$ circuit at resonance, the phase difference between voltage and current is