JEE Main 2026 Physics question
An a.c. source of angular frequency ω is connected across a resistor R and a capacitor C in series. The current is observed as I. Now the frequency of the source is changed to ω/4, (keeping the voltage unchanged) the current is found to be I/3. The ratio of resistance to reactance at frequency ω is
Answer: (C)
Solution
At ω/4, Xc becomes 4Xc. From V/√(R²+Xc²)=I and V/√(R²+16Xc²)=I/3: (R²+16Xc²)/(R²+Xc²)=9, giving 7Xc²=8R², so R/Xc=√(7/8).