12th Class Physics MCQS
In LR circiut which one of the following statements is correct?
The inductive reactance increases with frequency
L and R opposes each other
The inductive reactance decreases with frequency
R value increases with frequency
An alternating voltage is given by 20 sin 157 t. Th efrequency of alternating voltage is:
50 Hz
100 Hz
75 Hz
25Hz
An electromagnetic wave goes from air to glass which of the following does not change?
X-rays
Ultra violet radiation
Ultra sond waves
Radio waves
In chopke coil the resistance XL an resistance R are:
XL>>R
XL<<R
XL=R
XL=
The reactance is the ratio of
Irms/Vrms
Vrms/Irms
Vmax x Vrms
Vrms x Irms
In A.C circuit through a capacitor which one is:
Both will be in phase
Current lags behind voltage by 90?
Current leads voltage by 90?
None of above
If Io is the peak value of current, then its root mean square value is given by
2 Io
Io
0.7 Io
The highest value reached by the voltage or current is one cycle is called:
Peak to peak value
Root mean square value