A resistor ‘R’ and 2µF capacitor in series is connected through a switch to 200 V direct supply.
Question:

A resistor ‘R’ and $2 \mu \mathrm{F}$ capacitor in series is connected through a switch to $200 \mathrm{~V}$ direct supply. Across the capacitor is a neon bulb that lights up at $120 \mathrm{~V}$. Calculate the value of $\mathrm{R}$ to make the bulb light up $5 \mathrm{~s}$ after the switch has been closed. $\left(\log _{10} 2.5=0.4\right)$

1. $2.7 \times 10^{6} \Omega$

2. $3.3 \times 10^{7} \Omega$

3.  $1.3 \times 10^{4} \Omega$

4.  $1.7 \times 10^{5} \Omega$

Correct Option: 1

Solution: