Which of the following is true about Electromagnets? When the current is shut off, the magnetic field disappears.
they do not easily lose their magnetism.
they are naturally-occurring magnets
All of the above
None of the above​

Physics make-up packetname_cle14. an observer hears a sound with a frequency of 400 hz. if the speed of sound is 340 m/s,what is the wavelength of the sound? a. 0.85 mb. 1.2 mc. 2.75 m13.6 m15. as sound travels from steel into air, its speed decreases. if the frequency of the wavedoesn't change, what happens to its wavelength? a. it increases(b) it decreasesc. it remains the samed. there is not enough information given

Thomas his older brothers, who own a junk yard, on the weekends to earn extra money. he likes to them push broken-down cars to the back of the junk yard because it makes him feel strong. last saturday, they pushed three cars with different weights, and he noticed he used different amounts of force for each one. the cars were the following weights: white car: 2,700 kg red car: 1,500 kg blue car: 2,100 kg think about how much force is needed to move each car. which correctly lists the cars in order from the most to least amount of force needed to move them? a) white, blue, red b) blue, red, white c) red, white, blue d) white, red, blue

Apair of 10μf capacitors in a high-power laser are charged to 1.7 kv.a. what charge is stored in each capacitor? b. how much energy is stored in each capacitor?