An 18,000-watt radio station transmits at 680 khz. calculate the energy of a single photon at the transmitted frequency.

The electric field direction is defined by the direction of the force felt by (select one of the following answers): 1. a negative charge. 2. a positive charge. 3. both positive and negative charges.

Ahot-air balloon takes off from the ground traveling vertically with a constant upward acceleration of magnitude g/4. after time interval δt, a crew member releases a ballast sandbag from the basket attached to the balloon. how many seconds does it take the sandbag to reach the ground? (express your answer in terms of δt)

The junction rule describes the conservation of which quantity? note that this rule applies only to circuits that are in a steady state.