During which period of the Paleozoic Era did the first amphibians evolve?

Permian

Devonian

Cambrian

Carboniferous

An electric motor converts electric energy into what type of energy? potential thermal magnetic mechanical

A thin lens is made from a material with refractive index of 1.20. This lens may be used in either air (n = 1.00) or water (n = 1.33). Which of the following is true? A.

How long will it take to heat 3kg of water from 28c to 88c in an electric kettle taking a current of 6 ampere from am emf source of 220 volt

What is buoyant force? A. A force within a fluid that pushes downward B. The attraction between two identical molecules C. The attraction between two different molecules D. A force within a fluid that pushes upward

A student makes a transverse wave by shaking a rope tied to a doorknob up and down. Which statement accurately describes the wave in the rope? a-Each part of the rope moves in the same direction as the wave.

Is momentum conserved in the collision?

Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?

In a laboratory, you determine that the density of a certain solid is 5.23*10-6kg/mm3. Convert this density into kilograms per cubic meters.

List the solar objects in correct order from the Sun. Venus Earth Mercury Saturn Neptune Mars Jupiter Asteroid Belt The Sun Uranus

The power exerted by a muscle is the product of the force exerted and the velocity of contraction. The area of which of these shaded regions represents the power exerted while a weight is lifted at maximum speed?