If ∣∣∣−→F1×−→F2∣∣∣=−→F1.−→F2, then ∣∣∣−→F1+−→F2∣∣∣ is
Find the percentage of tall plants in F1 and F2 generation from the image given below.
If two thin lenses of focal length f1 and f2 are held in contact then the focal length of the combination will be