Explanation:
speed= frequency * wavelength
20=x*4
frequency=20/4
=5Hz
period=1/frequency
1/5
=0.2
Answer:
Gravity dams are so named because they are held to the ground by gravity – they weigh a lot, and are typically made from concrete or stone. Engineers must de-water the river where the dam is meant to be built. This is done by diverting the river through a tunnel that runs around the intended construction zone.
Most likely, the light wave will be absorbed by the wall. Without any information as to the size and color of the wall, the location and size of the hole, or the location of the light wave, this is a generalized probability problem. For all of the places the light could be, it's more likely that it hits the wall than the hole (if the hole is less than 50% of the area of the wall).
Answer:
Option c and d
Explanation:
The two mechanical devices which are used in laboratories for accurate measurement of small distances or small objects are calipers and micrometer.
Micrometer is a mechanical device used in laboratories like that of a screw gauge. It is used for the measurement of thickness of objects, length and the depth of the small objects which can be measured by holding the object in between the spindle and anvil of the micrometer.
Calipers is another mechanical device like that of vernier calipers used in laboratories for measurement of small distances, usually the distance between the opposing faces of the object. The measurement is usually taken on a digital display, a dial or a scale that is ruled.
The distance is measured by adjusting the tips of the caliper holding the object on a ruler.
