CIL 2017 | System | Question: 85

Question

State TRUE or FALSE for the following.

1. A sine wave with a phase of $180^{\circ}$ starts at time $0$ with a zero amplitude. The amplitude is decreasing.
2. If a signal changes instantaneously, its frequency is zero.
3. In bipolar encoding, we use three voltage levels: positive, negative and zero.
4. Infrared signals can be used for short-range communication in a closed area using ground propagation.

• A. $\text{(i)}$ TRUE, $\text(ii)$ FALSE, $\text{(iii)}$ TRUE, $\text{(iv)}$ FALSE
• B. $\text{(i)}$ TRUE, $\text(ii)$ TRUE, $\text{(iii)}$ TRUE, $\text{(iv)}$ FALSE
• C. $\text{(i)}$ FALSE, $\text(ii)$ TRUE, $\text{(iii)}$ FALSE, $\text{(iv)}$ FALSE
• D. $\text{(i)}$ TURE, $\text(ii)$ TRUE, $\text{(iii)}$ FALSE, $\text{(iv)}$ FALSE