If the power supplied by the 20 V voltage source shown in figure below is 60 W then, the power supplied by the unknown circuit element (x) will be
we know that
In the network of figure shown below, I1 = 0.05 A, I2 = 0.1 A , R = 50 Ω. The unknown current source has strength of i, If 100 J of energy is delivered to I2 in 1 min, the magnitude of i will be
energy dissipated in where p=vi
Since power is constant, therefore
Applying KCL at node v, we have
The energy required to move 120 C charge through 3 V is
W=QV=120 X 3 = 360J
For a given voltage, four heating coils will produce maximum heat, when connected
Maximum heat produced is
for P to be maximum, Req should be minimum which is minimum of all four coils are connected in parallel.
Given figure shows a plot of d.c. voltage applied to a resistor of 5 Ω for 15 seconds. The total energy consumed by the resistor is
energy = power x time
Hence, the heat consumed by the resistor
= 1140 J
The charge in a capacitor is given by
if the voltage across this capacitor be v(t) = sin t, the current i(t) through the capacitor is
The current through.the capacitor is
The unit of reactive power is
Active power does do work, so it is the real axis. The unit for power is the watt (symbol: W). Apparent power is often expressed in volt-amperes (VA) since it is the product of rms voltage and rms current. The unit for reactive power is var, which stands for volt-ampere reactive.
The unit of electrical energy is
The given signal is
Given signal is a ramp signal f(t) = A(t), which is neither an energy signal nor a power signal.
The two voltage sources connected in parallel as shown below, must satisfy the conditions