If an electromagnet is made using a battery circuit and a steel nail, how can its magnetic strength increase? 1-wrap more coils of wire around the nail 2-use a longer nail 3-remove the plastic insulation from the wire coil 4-replace the nail with a copper rod

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line