Question

Select correct alternative :
Statement -1 : An electric dipole can not produce zero electric field at a point which is situated at finite distance from the dipole.
Statement -2 : Mass of a moving photon is proportional to ${\lambda }^{-1}$ .
Statement -3 : Equation of continuity for fluid is based on conservation of volume.

• A. FFF
• B. TTF
• C. TFF
• D. TTT

Answer 1

Answer: (B)

TTF

Statemen-1: The potential due to a electric dipole of moment (p) is:
$\varphi =\frac{1}{4\pi ϵ}\frac{\overrightarrow{p}.\hat{r}}{r^2}$
The electric field from a dipole can be found from the gradient of this potential which cannot be zero at a point which is situated at finite distance from the dipole.
Statemen-2: From de-Brogli formula: The mass of a moving electron is given by:
$m=\frac{h}{\lambda v}$. So, mass of a moving photon is proportional to ${\lambda }^{-1}$
Statemen-3: A continuity equation in physics is an equation that describes the transport of a conserved quantity. Since mass, energy, momentum, electric charge and other natural quantities are conserved under their respective appropriate conditions, a variety of physical phenomena may be described using continuity equations.

So the answer is TTF.