When we rub a glass rod with a silk cloth then________________?
(A) glass rod acquires negative charge while silk acquires positive charge
(B) glass rod acquires positive charge while silk acquires negative charges
(C) both glass rod and silk acquire negative charge
(D) both glass rod and silk acquire positive charge
A coil of wire is arranged with its plane perpendicular to a uniform magnetic field o flux density B. when the radius of the coil increases from r1 to r2 in time Δt then what is the emf induced in the coil ?
(A) ωB/r22-r12/Δt
(B) ωB(r2-r1)2/Δt
(C) ωB(r22-r12)/Δt
(D) ωB(r22+r12)/Δt
The alternating current has frequency of 106 Hz in such a way that time period for completion of cycle is_______________?
(A) 1Hzs
(B) 1.5Hzs
(C) 106sec
(D) 1sec
Self inductance of a coil depends upon________________?
(A) current flowing
(B) number of turns per unit length
(C) voltage produce
(D) all
The only difference between construction of D.C generator and A.C generator is that of_______________?
(A) carbon brushes
(B) coil
(C) commutator
(D) magnetic field
Two oppositely charged balls A and B attract third conducting ball C when placed near them turn by turn. Then ball C must be______________?
(A) positively charged
(B) electrically neutral
(C) negatively charged
(D) positively and negatively charged
capacitor is to have an energy content of 20J it must be placed across a potential difference of________________?
(A) 4 volts
(B) 9 volts
(C) 2 volts
(D) 1 vol
A 25eV electron has a speed of______________?
(A) 2 x 106m/sec
(B) 3 x 106m/sec
(C) 5 x 106m/sec
(D) 4 x 106m/sec