Aptitude Test Problems in Physics Science for Everyone by S Krotov ( PDFDrive.com )

Fig. 102

Fig. 103

3. Electricity and Magnetism 91

Determine the amount of heat Q liberat-

ed in the resistor after switching the key

K.
3.44. An electric circuit consists of a cur-

rent source of emf g and internal resistance

r , and two resistors connected in paral-

lel to the source (Fig. 102). The resistance

R 1 of one resistor remains unchanged, while

the resistance R2 of the other resistor can

be chosen so that the power liberated in .this

resistor is maximum.

Determine the value of R 2 corresponding

to the maximum power.

3.45. A capacitor of capacitance C 1 is dis-

charged through a resistor of resistance R.

When the discharge current attains the

value / 0 , the key K is opened (Fig. 103).