A generator gives e = e₀sinω t, with e₀ = 170 V and f = 60 Hz…

Step 1. At $2.0$ ms. The angle is $\omega t = 377\ \text{rad/s} \times 0.0020\ \text{s} = 0.754\ \text{rad}$. Then $e = 170\ \text{V} \times \sin 0.754 = 170\ \text{V} \times 0.685 = 116.4\ \text{V}$.

Step 2. The first time at $100$ V. We want $t$, so $\sin\omega t = \dfrac{100}{170} = 0.588$. The first angle with this sine is $0.629$ rad. So $t = \dfrac{0.629\ \text{rad}}{377\ \text{rad/s}} = 1.67\ \text{ms}$.