The equation for electrical power is<span>P=VI</span>where V is the voltage and I is the current. This can be rearranged to solve for I in 6(a).
6(b) can be solved with Ohm's Law<span>V=IR</span>or if you'd like, from power, after substituting Ohm's law in for I<span>P=<span><span>V2</span>R</span></span>
For 7, realize that because they are in parallel, their voltages are the same.
We can find the resistance of each lamp from<span>P=<span><span>V2</span>R</span></span>Then the equivalent resistance as<span><span>1<span>R∗</span></span>=<span>1<span>R1</span></span>+<span>1<span>R2</span></span></span>Then the total power as<span><span>Pt</span>=<span><span>V2</span><span>R∗</span></span></span>However, this will reveal that (with a bit of algebra)<span><span>Pt</span>=<span>P1</span>+<span>P2</span></span>
For 8, again the resistance can be found as<span>P=<span><span>V2</span>R</span></span>The energy usage is simply<span><span>E=P⋅t</span></span>
Answer: 9.98 *10^-19 J
Explanation: In order to explain this probelm we have to consider the balance enegy for photoelectric effect.
h*f-W=Ek where h is the Planck constant and W the work function and Ek the kinetic energy. f is the frequency of light.
W=h*f-Ek=6.62*10^-34*2.4*10^15-5.9*10^-19=9.98*10^-19J
Answer:
(A) Torque required is 21.205 N-m
(b) Wok done will be equal to 1199.1286 j
Explanation:
We have given moment of inertia 
Wheel deaccelerate from 135 rpm to 0 rpm
135 rpm = 
Time t = 8 sec
So angular speed 
and 
Angular acceleration is given by 
Torque is given by torque 
Work done to accelerate the vehicle is
