Q 21 :

As shown in the figure, a configuration of two equal point charges (q0=+2μC) is placed on an inclined plane. The mass of each point charge is 20 g. Assume that there is no friction between the charge and the plane. For the system of two point charges to be in equilibrium (at rest), the height h=x×10-3 m. The value of x is ______. 

(Take 14πε0=9×109 N m2C-2,g=10 ms-1)               [2023]

[IMAGE 136]



(300)

For equilibrium along the plane

mgsinθ=14πε0×q02(hcosec30°)2

  h2=14πε0×q02mgcosec30°=9×109×(2×10-6)20.02×10×2

  h=3×104×2×10-62=0.3 m=300 mm