The hot resistance of the bulb’s filament is higher than its cold resistance because the temperature co-efficient of the filament is___________________?
(A) zero
(B) negative
(C) positive
(D) about 2 ohms per degree
A closed switch has a resistance of_____________?
(A) zero
(B) about 50 ohms
(C) about 500 ohms
(D) infinity
Two resistances Rl and Ri are connected in series across the voltage source where Rl>Ri. The largest drop will be across______________?
(A) Rl
(B) Ri
(C) either Rl or Ri
(D) none of them
The four bulbs of 40 W each are connected in series swift a battery across them, which of the following statement is true_______________?
(A) The current through each bulb in same
(B) The voltage across each bulb is not same
(C) The power dissipation in each bulb is not same
(D) None of the above
In a lamp load when more than one lamp are switched on the total resistance of the load_____________?
(A) increases
(B) decreases
(C) remains same
(D) none of the above
When one leg of parallel circuit is opened out the total current will______________?
(A) reduce
(B) increase
(C) decrease
(D) become zero
It becomes more difficult to remove_________________?
(A) any electron from the orbit
(B) first electron from the orbit
(C) second electron from the orbit
(D) third electron from the orbit
Whether circuit may be AC. or D. C. one, following is most effective in reducing the magnitude of the current?
(A) Reactor
(B) Capacitor
(C) Inductor
(D) Resistor
A glass rod when rubbed with silk cloth is charged because__________?
(A) it takes in proton
(B) its atoms are removed
(C) it gives away electrons
(D) it gives away positive charge
Two bulbs of 500 W and 200 W rated at 250 V will have resistance ratio as________?
(A) 4 : 25
(B) 25 : 4
(C) 2 : 5
(D) 5 : 2