Correct option (A – q,r) ; (B – p,r) ; (C – q, r) ; (D – q, r)
(A) when resistance of rehostate is increased then current in circuit is decreased. so brightness will decrease.
(B) when resistance of bulb is increased then potential difference is increased across it. so brightness will increase.
(C) from t=0 to steady state, q will increase on capacitor so potential difference will increase across it and current will decrease so brightness will decrease.
(D) same as C.