Dimensions of stress are :

The energy required to break one bond in DNA is 10^-20 J. This value in eV is nearly :

In an experiment, the percentage of error occurred in the measurement of physical quantities A, B, C and D are 1%, 2 %, 3 %and 4 % respectively. Then the maximum percentage of error in the measurement X, where
X = $${{{A^2}{B^{1/2}}} \over {{C^{1/3}}{D^3}}}$$, will be :

A student measured the diameter of a small steel ball using a screw gauge of least count 0.001 cm. The main scale reading is 5 mm and zero of circular scale division coincides with 25 divisions above the reference level. If screw gauge has a zero error of –0.004 cm, the correct diameter of the ball is