Six charges +q, $$-$$q, +q, $$-$$q, +q, and $$-$$q are fixed at the corners of a hexagon of side d as shown in the figure. The work done in bringing a charge q0 to the centre of the hexagon from infinity is
($${\varepsilon _0}$$ - permittivity of free space)
An astronomical refracting telescope is being used by an observer to observe planets in normal adjustment. The focal lengths of the objective and eye piece used in the construction of the telescope are 20 m and 2 cm respectively. Consider the following statements about the telescope :
(a) The distance between the objective and eye piece is 20.02 m
(b) The magnification of the telescope is ($$-$$) 1000
(c) The image of the planet is erect and diminished
(d) The aperture of eye piece is smaller than that of objective
The correct statements are :
The magnetic flux linked to a circular coil of radius R is
$$\phi = 2{t^3} + 4{t^2} + 2t + 5$$ Wb
The magnitude of induced emf in the coil at t = 5 s is
Three vessels of equal capacity have gases at the same temperature and pressure. The first vessel contains helium (monoatomic), the second contains fluorine (diatomic) and the third contains sulfur hexafluoride (polyatomic). The correct statement, among the following is :