Colour vision in human eyes is the function of photoreceptor cells named

The radii of curvature of the faces of a double convex lens are 10 cm and 20 cm. The refractive index of the glass is 1.5. What is the power of this lens?

The time period of a simple pendulum made by using a thin copper wire of length L is T. Suppose the temperature of the room in which this simple pendulum is placed increases by 30$$^\circ$$C. What will be the effect on the time period of the pendulum?

Which one of the following physical quantities has the same unit as that of pressure?