How do you find the focal length of an lens experimentally​

Place the convex lens on a 'V' stand. . ii) Light a candle and take it far away from the lens along the principal axis. iii) Adjust the screen on the other side of the lens to get a clear image on it. iv) Measure the distance between the 'V' stand and the screen which gives a rough idea of the focal length of the lens.

current flows in a wire

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table