The answer is : B. The compass will spin exactly 360 Degrees
Compass will point out to the earth's magnetic field. If we change the direction of the current , we created an effect which make the compass detect the magnetic field in the exact opposite direction, that is why it will flip exactly 180 degrees
Waves carry energy from one place to another. Because waves carry energy, some waves are used for communication, eg radio and television waves and mobile telephone signals. ... Some types of waves need to be transmitted through matter, either a solid, liquid or a gas. For example, water waves have to travel in water.