What happens to the strength of the magnetic field as you come closer to the current carrying wire

A100-watt light bulb illuminates a solar cell. the electricity from the solar cell operates a water pump that delivers 1 watt of power. what is the efficiency of the system?

Which stable element is used to determine the age of volcanic rock? a- argon b- carbon-14 c- potassium d- carbon-12

Many science fiction movies and tv shows have detected using a nuclear weapon to destroy astroids what problems does plait see with this plan