## Kumar Ketan is teaching live on Unacademy Plus

unacademy All Structured live courses Complete Physics Chemistry & Math Weekly quizzes & doubt clearing plus KUMAR KETAN Referral ID: KumarKetan

An n-p-n transistor in a common-emitter mode is used as a simple voltage-amplifier with a collector-current of 4 mA. The terminals of a 8 V battery is connected to the collector through a load-resistance R and to the base through a resistance RB. The collector-emitter voltage VCE 4 V, the base emitter voltage VBE 0.6 V and the current amplification factor Bdc 100. Then (a) RL 1 kQ, RB-185 k (b) R 2 kS2 RR (c) RL-2 kQ, RB-15 k (d) RL = 185 kQ, RB-1

An n-p-n ransistor in a common emitter mode with connections as given is shown in figure. Collector emitter voltage, VCE = Vcc-Ic RL RL=VCC-VCE CE V BE 8 V

8V 4V 4x10-3 A dc Ic 4x10 Bdc 100 3 A=4 10-5 A Base-emitter voltage, VBE Vcc IB RB 5 4 10- A 1.85 105 185 k

The resistance is R =-, where V= 100 5 volts and I - 10 + 0.2 amperes. What is the total error in R? (a) 5% (c) 5.2% (b) 7% 2

0.2 5 100 100 +- 100 = 7 % 10

Students x,, x2, X3X, perform an experiment for measuring the acceleration due to gravity (g) using a simple pendulum. They use different lengths of the pendulum and record time for different number of oscillations. The observations are shown in the table. Least count for length 0.1 cm, Least count for time = 1 s

Students Length of No. of Time period pendulum oscillations lof pendulum cm 100.0 400.0 100.0 X4 400.0 20 10 10 20 20 40 20 40 2 3 1 If Pl, P2, P3 and P4 are the % error in g for students XI, X2, X3 and X4 respectively then (a) P1 P3 (c) P, is minimum (d) P2-P4 (b) P3 is maximum

8 Therefore 100 P=(01+2(1) 100 400 / 2.47 lT