A heat engine has a total heat input of 1.3 kJ and a thermal efficiency of 35 percent. How much work will it produce

455Joules

Explanation:

Efficiency is expressed as;

Efficiency = Work output/Work input × 100%

Given

Efficiency = 35%

Work input = 1.3kJ = 1300Joules

Required

Work output

Substitute into the formula to get work output as shown:

35 = work output/1300 × 100

35 = work output/13

Work output = 35×13

Work output = 455Joules

Hence the machine will produce 455Joules of work

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.