What is the purpose of the metal core in an electromagnet? a) it is magnetized and induces a current in the solenoid to decrease the magnetic field strength. b) it is magnetized and induces a current in the solenoid to increase the magnetic field strength. c) it is magnetized by the field of the solenoid and increases the magnetic field strength. d) it is magnetized by the field of the solenoid and decreases the magnetic field strength.

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.

Two students, each riding bicycles, start from the same apartment building and ride to the same building on campus, but each takes a different route. the first student rides 1100 m due east and then turns due north and travels another 1430 m before arriving at the destination. the second student heads due north for 1930 m and then turns and heads directly toward the destination.at the turning point, how far is the second student from the destination?

Frequency of electromagnetic waves that a radio station is assigned is called