A single phase 240 V, 1 kW heater is connected across single phase 240 V, 50 Hz supply through an SCR. For firing angle delay of 90˚, calculate the power absorbed in the heater element.

Resistance of heater, R = V²/P
R = 57.6 ohm

RMS value of voltage through controlled SCR = (Vm/2π)*(1 + cosα)
= 120 V

Power absorb by heater = Vrms²/R
= 120²/57.6
= 250 W

The relation between electric intensity E, voltage applied V and the distance d between the plates of a parallel plate condenser is

The relation between electric intensity E, voltage applied V and the distance d between the plates of a parallel plate condenser is given by:
V = E*L
E = V/L

The wind speed increases with height because of

Wind speed increases as the height from the ground increases mainly due to the decrease in the friction produced by land terrain.

Choose the best option from the given alternatives which can be substituted for the given word/sentence.
A person who kills somebody especially for political reasons

If the velocity of electromagnetic wave in free space is 3 × 10⁸ m/s, then the velocity in a medium with εr of 4.5 and μr of 2 would be

Speed of EM wave in medium = C/√(εr*μr)
= (300000000)/√9
= 300000000/3
= 100000000
= 1*10⁸ m/s

A three-phase, 4-pole, 50 Hz induction motor runs at 1425 rpm. Find out the percentage slip of the induction motor.

Slip, s = (Ns - Nr)/Ns
Ns = 120f/P
Ns = 1500 rpm

s = (1500 - 1425)/1500
s = 0.05
%s = 5%