Can someone please help me with this question please and thank you

4. A student creates a home made solenoid by wrapping copper wire around a toilet paper dispenser. As shown below, when attached to a power supply of fixed voltage, the solenoid produces a magnetic field within it of 8.40 x 10" T. a) Based on the polarity of the power supply, use the Right-Hand-Rule to determine the direction of conventional current flowing in the coils of the solenoid. Draw arrows directly on the diagram Label the North and South ends of the electromagnet.. I mark b) Determine the new strength of the magnetic field if the following parameters are changed: i. The student adds three times as many turns of wire to the solenoid, while the length and current stay the same. I mark ii. The current and tums are kept the same but the coils are spread out so that the solenoid is 1.5 times longer. ii. I mark iii. The current and length is doubled, with 1/4 as many turns in the solenoid. ini. 2 marla