Question

The fact that an electric current generates a magnetic field has allowed people to 20. cons ruct which of the following devices? (Choose as many as apply.) (A) ammeters (B) voltmeters (C) motors (D) none of these When a magnet is plunged into a coil of wire, the magnitude of the current induced is affected by which of the following? (Choose as many as apply.) (A) the speed with which the magnet is plunged into the coil (B) the number of loops in the coil (C) the resistance of the material of which the coil is made (D) the color of the magnet A device that changes mechanical energy to electrical energy is a (A) magnetizer (B) transformer (C) motor (D) generator. Alternating current is run through a primary loop of wire. A nearby secondary loop of wire will experience which of the following? (Choose as many as apply.) (A) a current when the current is first turned on in the primary loop, but will not experience a current after that (B) no current when the current is first turned on in the primary loop, but will experience a current after that (C) a current when the current is first turned on in the primary loop and as long as there is current in the primary loop (D) a current because it is in a changing magnetic field (E) a current because it is in an unchanging magnetic field. In a transformer, if the primary has more loops than the secondary, then (A) the voltage in the secondary is stepped up (B) the voltage in the secondary is stepped down (C) the current in the secondary is stepped down. An electromagnetic wave (Choose as many as apply.) (A) is composed of electric and magnetic waves which reinforce each other (B) is composed of a changing electric field which does not produce a changing magnetic field (C) always travels at the speed of light in a vacuum (D) travels at various speeds in a vacuum. 25
Help pls answer all .

Answer 1