The bob of a simple pendulum has a mass of 40 g and a positive charge of `4.0 xx 10 ^(-5) C` . It makes 20 oscillations in 45 s. A vertical electric field pointing upward and of magnitude `2.5 xx 10^ 4 NC^(-1)` is switched on. How much time will it now take to complete 20 oscillations?

Explanation

To solve the problem, we will follow these steps:

### Step 1: Calculate the time period of the pendulum without the electric field (T1)

Given:
- Mass of the bob, \( m = 40 \, \text{g} = 40 \times 10^{-3} \, \text{kg} \)
- Number of oscillations = 20
- Time for 20 oscillations = 45 s
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