A 30w light bulb uses 600J of electrical energy in a certain period of time. In that time, it produces 450 J of light energy. The rest of the energy is wasted calculate the efficiency of the light bulb

An electric circuit can have no current when a switch is closed. True False

A bumblebee buzzes past you at 3 m/s. The frequency of the hum made by its wings is 152 Hz. Assume the speed of sound to be 342 m/s. What is the observed frequency of the hum as the bumblebee approaches you?

The discoveries of astronomers like copernicus and galileo

Why are electrons in different places and not together?

Explain why total internal reflection has make communication much faster through the use of fibre optic cables.

While spinning in a centrifuge a 70.0 KG astronaut experiences an acceleration of 2.00g, or twice the acceleration due to gravity on the earth. What is the centripetal force acting on her? A.) 6.86*10^3N B.) 1.37*10^3N C.) 1.40*10^2N D.) 3.46*10^4N

What will occur if the steepness of an inclined plane is decreased?

A 12,000-N car is raised using a hydraulic lift, which consists of a U-tube with arms of unequal areas, filled with incompressible oil with a density of 800 kg/m3 and capped at both ends with tight-fitting pistons.

The standard metric units of measurements for electric field strength are?

What steps are involved in converting potential energy to kinetic energy, or kinetic energy to potential energy?