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6.

Four point charges -Q, -q,2q and 2Q are placed, one at each corner of the square. The relation between Q and q for which the potential at the centre of the square is zero is


A) Q = -q

B) Q = -1/q

C) Q = q

D) Q = 1/q



7.

In Young's double slit experiment the two slits are illuminated by light of wavclenght 5890Å and the distance between the fringes obtained on the screen is 0.2º. If the whole apparatus is immersed in water then the angular fringe width will be, if the refractive index of water is 4/3.


A) 0.30º

B) 0.15º

C) 15º

D) 30º



8.

A steel wire of length l has a magnetic moment M. It is then bent into a semicircular arc. The new magnetic moment is


A) $\frac{M}{\pi}$

B) $\frac{2M}{\pi}$

C) $\frac{3M}{\pi}$

D) $\frac{4M}{\pi}$



9.

  In the circuit shown the cells A and B have negligible resistances. For VA 12V,R1 = 500 Ω and R = 100Ω the galvanometer  (G) shows no deflection. The value of VB is :

1142021960_download (1).png


A) 4 V

B) 2 V

C) 12 V

D) 6 V



10.

In a photoelectric effect measurement, the stopping potential for a given metal is found to be V0 volt when radiation of wavelength λ0 is used.lf radiation of wavelength 2λ0 is used with the same metal then the stopping potential (in volt) will be


A) $\frac{V_{0}}{2}$

B) $2V_{0}$

C) $V_{0}+\frac{hc}{2e\lambda_{0}}$

D) $V_{0}-\frac{hc}{2e\lambda_{0}}$



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