1.does the current in an AC circuit lags,leads remains in phase with the voltage of frequency (f) applied to the circuit, when 
(i)f=fr   (ii)f<fr   (iii) f>fr,where fr is the resonant frequency?
 
2.what happens to the focal length of lens when it is immersed in water?

Asked by Karishma | 7th Mar, 2015, 10:33: PM

Expert Answer:

2. When a convex lens is immersed in water there will be an increase in focal length and this is because the refractive index of glass with respect to water is less than the refractive index of glass with respect to air.
 
Note: Kindly ask the other question as a separate query.

Answered by Faiza Lambe | 7th Mar, 2015, 11:53: PM