Denver constructs an electric bell as shown in the diagram below. He then turns the switch on to test the bell. Denver notices that the hammer moves a bit toward the gong, but does not quite reach the gong. Which of the following should Denver do to best increase the chances of making the bell ring?
A.
increase the length of the arm supporting the hammer and use a heavier hammer
B.
increase the current produced by the battery and the number of coils around the electromagnet
C.
decrease the size of the gong and use a larger hammer
D.
decrease the size of the gong and the number of coils around the electromagnet