Question 7
The Atlantic torpedo
is a large electric fish capable of generating a voltage of 220 V between its tail
and its head. This drives a pulse of current of 15 A lasting for a time of 2.0
ms. The fish produces 200 pulses per second.
What is the average
power output of the fish?
A 33
W B 1.3
kW C 3.3
kW D 6.6
kW
Reference: Past Exam Paper – November 2015 Paper 11 Q33
Solution:
Answer: B.
A
pulse of current of 15 A lasts for 2.0 ms.
Power
= VI and Power = Energy /
time
Energy
= Power × time
Energy
of each pulse = VIt
Energy
of each pulse = 220 × 15 × 2.0×10-3 = 6.6 J
The fish
produces 200 pulses per second (this quantity is the number of pulses per
second).
Average
power = total energy / time
Average
power = no. of pulses × energy of 1 pulse / time
Average
power = (no. of pulses / time) × energy of 1 pulse
(no.
of pulses / time) = 200 s-1
Average
power = (no. of pulses / time) × energy of 1 pulse
Average
power = 200 × 6.6
Average power = 1320 W = 1.3 kW
No comments:
Post a Comment
If it's a past exam question, do not include links to the paper. Only the reference.
Comments will only be published after moderation