4. Electricity and magnetism – Page 2

Exercise 4.2 D

Specify the resistance of one lamp and the total resistance. Both lamps are similar.

Tip: For lamps in series the total resistance is the sum of resistances.

Answer: Total resistance is $18\ \Omega$; the resistance of one lamp is $9{,}0\ \Omega$

Specify the resistance of one lamp and the total resistance. Both lamps are similar.

Tip: Switching the lamps in series the total resistance is the sum of resistances.

Answer: The resistance of one lamp is $9{,}5\ \Omega$; the total resistance is $19\ \Omega$

Specify the resistance of one lamp and the total resistance. Both lamps are similar.

Answer: Total resistance is $5{,}1\ \Omega$; the resistance of one lamp is $10\ \Omega$

Determine the resistance of the lamp.

Answer: $8{,}1\ \Omega$

Determine the internal resistance of the battery.

Answer: $0{,}60\ \Omega$

Determine the resistance of the wirewound resistor per unit length.

Answer: $40{,}7 \Omega /m$

Determine the resistance of the wirewound resistor per unit length.

Answer: $40{,}5 \Omega /m$

Specify the power of one lamp as well as the power of the lamps. Both lamps are similar.

Answer: Power of the lamps is 0,43 W; the power of a single lamp is 0,22 W

Specify the power of one lamp as well as the power of the lamps. Both lamps are similar.

Answer: Power of one lamp is 0,32 W; power of both lamps is 0,65 W

Specify the power of one lamp as well as the power of the lamps. Both lamps are similar.

Answer: Power of the lamps is 0,90 W; the power of one lamp is 0,45 W