In a solenoid, the current flowing through the wire is I and number of turns per unit length is n. This gives a magnetic field B inside the solenoid. If number of turns per unit length is increased to 2n, what will be the value of magnetic field in the solenoid?

Which one of the following statements is correct about the magnification of an optical microscope?

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?