A wire with a length of 50cm is tightly wound on the pencil rod for 30 turns, and the width of 30 turns is measured with a scale, then the diameter of the wire is () mm (2) μ M

A wire with a length of 50cm is tightly wound on the pencil rod for 30 turns, and the width of 30 turns is measured with a scale, then the diameter of the wire is () mm (2) μ M

The diameter is 500 / 30mm = 50 / 3mm
1um=10^-6mm.
It is 50 / 3 * 10 ^ 6um

A 50cm long wire is tightly wound on the pencil rod for 30 turns, and the width of 30 turns is 3cm measured with a scale. Then the diameter of the wire is () cm
If the number of turns is less than one, the measurement result will be biased. If the wire is wound without tight winding but with clearance, the measurement result will be biased

3cm/30=0.1cm
A few times, 3 / 29 > 0.1, too large
There is no close winding, obviously the width of 30 turns is less than 3cm, with a gap in the middle, and the diameter is less than 3cm

The thin wire is tightly wound on the log bar for 60 turns, and then the width is 3.6cm measured with a millimeter scale. Therefore, the diameter of the wire is?

3.6 divided by 60 = 0.06 cm