A beam of plane polarised light of large
cross-sectional area and uniform intensity
of 3.3 Wm^-2 falls normally on a
polariser (cross sectional area 3 $$ \times $$ 10^-4 m²) which
rotates about its axis with an angular speed
of 31.4 rad/s. The energy of light passing through
the polariser per revolution, is close to :

The specific heat of water
= 4200 J kg^-1K^-1 and the latent heat of
ice = 3.4 $$ \times $$ 10⁵ J kg^–1. 100 grams of ice at
0^oC is placed in 200 g of water at 25^oC. The
amount of ice that will melt as the temperature
of water reaches 0^oC is close to (in grams) :

Take the breakdown voltage of the
zener diode used in the given circuit as 6V.
For the input voltage shown in figure below,
the time variation of the output voltage is:
(Graphs drawn are schematic and not to scale)

A small bar magnet placed with its axis
at 30^o with an external field of 0.06 T
experiences a torque of 0.018 Nm. The
minimum work required to rotate it from its
stable to unstable equilibrium position is :