Check the state of polarization of the room lights by looking at the room lights through one of the polarizers and rotating it through 360. Do you observe any signigicant variation in the intensity of the light transmitted through the polarizer

No, there wasn't any variation in the light intensity at 360 degrees.

During the rotation, rotating through an angle of 90° gradually brought the intensity to a maximum. Rotating by another 90° degrees brought the intensity to a minimum at some point. Rotating by another 90° brought it back to its maximum and then another 90° brought it to its initial intensity.

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg