Vectors and Equilibrium
If the magnitude of dot product and cross product of two vectors is 6√3 (6 under root 3) and 6 respectively. The angle between the vectors is?
A * B = AB sin ɵ = 6 ….. (i)
A.B = AB cos ɵ = 6√3 …(ii)
Dividing (i) by (ii) : AB sin ɵ / cos ɵ = 6 / 6√3
Tan ɵ = 1 / √3 or ɵ = 30o
A parallel beam of white light is incident normally on a different grating. It is noted that the second order and third order spectra partially overlap. Which wavelength in third order spectrum appears at the same angle as the wavelength of 600 nm in the second order spectrum?
Note that nλ should be constant.
2 * 600 = 1200
Now 3 * x = 1200, solving gives x = 400nm
Which of the following basic forces is short range?
- Weak nuclear forces
- Strong nuclear forces
- Gravitational force
- i only
- iii only
- i and ii only
- ii and iii only
i and ii only
Weak nuclear forces and strong nuclear forces are both short range forces which are effective only within sub-nuclear distances. Gravitational, electromagnetic and electric force are all long range.