3. (a) since circuit has only inductor and
generator, inductor voltage equals emf; use
Ohm's law (b) frequency is 8 times larger
so inductive reactance also 8 times larger
making current 1/8 as much.
4. Frequency has no effect since there is
no reactance in the circuit; use Ohm's law.
(0.60 A)
11. (a & b) emf or current will reach
maximum when the sin of the angle is a max,
or at (pi)/2; set the angle equal to (pi)/2
and solve for the time. (c) decide which
is leading, emf or current; ELI the ICE man
(d) use Ohm's law and the reactance equation.
15. Follow the steps in the sample problems
20 (a) voltage across generator is emf of
circuit (36 V) (b) from the phasor diagram,
we can see how the voltage drops across all
three circuit elements are related to the
emf. For the resistor, V = IRcos(phi) (27.3
V) (c) 17.0V (d) -8.34 V (e) sum of (b) (c)
& (d)
40. (a) power factor = cos (phi) (0.743)
(b) phase angle is neg. so current leads
emf (c) ELI the ICE man (d) check resonance
requirements (e) use eqn 36-26 to check on
resistor; answer to (c) gives capacitor answer;
can we tell if there is an inductor? (f)
use eqn 36-33 (33.4 W) (g) huh?
45. (a) Ratio of turns gives secondary voltage
(b) Find current drawn by secondary circuit
resistance; ratio of turns will now give
primary current.
1. plug in numbers to find numerical value;
justify unit analysis
3. Refer to sample problem 37-1; there are
two places where the situation in the problem
will occur, one where r < R and one where
r > R. For r < R, use function for
B derived in sample problem. Of course B
max will be where r = R. For r > R, use
Ampere's law to write expression for B, then
relate to B max/2
6. Using eqn 37-8, the change in flux is
change in AE, and E = V/d. Change in flux
is caused by change in V
7. Using eqn 37-8; change in flux is change
in AE. Area is not changing but E is. E =
V/d and V is what is changing so write eqn
in terms of dV/dt.