When you turn on a battery-operated device, an electrical circuit is

When you turn on a battery-operated device, an electrical circuit is closed.

Explanation:

A circuit works, only when it is closed. When we turn on the battery-operated device, the circuit is closed & complete. Hence, the current will flow across the circuit.

Only closed circuits work (current flows through them). No current can flow in an open circuit.

Diagram attached:

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s