What does a virus look like

The speed of light in a material is 0.50 c. what is the critical angle of a light ray at the interface between the material and a vacuum?

When a light bulb shines, it gives off light energy and energy. a. heat b. potential c. chemical d. electrical

Question 11 of 13 (1 point) jump to question: a stairway, ladder, or ramp must be present in excavations in which of the following situations? a. all trenches must have access/egress b. the trench is more than 15 feet wide but only 1 ½ feet deep c. the trench is more than 4 feet deep and the devices must be within 25 feet of all workers