a light ray travels from air (n-1) into a second medium at an angle of 20 degree. The light is refracted inside the second medium at an angle of 15 degree. What is the index of refraction of the second medium?

True or false: the revolution of the earth creates day and night as it rotates around the sun

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

A2k pendulum has a speed of 1 m/s at a height of 1/2 meter