A, B, C and D are four lamps connected to a battery of 60 𝑉 as shown in the figure.

Answer the following questions by analysing the circuit.

i. Are the bulbs arranged in a series or a parallel configuration?

ii. Describe any two benefits of this set of lighting in relation to your earlier response(i).

iii. Using accurate calculations, describe which lamp shines the brightest. 

                                             (OR)

As seen in the illustration below, PQ is a current-carrying conductor in the plane of the paper.

i. What direction does it produce magnetic fields in at points R and S?

ii. Where will the magnetic field's strength be greater given that 𝑟₁ > r₂. Explain.

iii. How would the magnetic field's direction change if the polarity of the battery attached to the wire was interchanged?

iv. Describe the rule that is used to determine the direction of the magnetic field for a straight current-carrying conductor.

i. From the given circuit, it is clear that lamps are arranged in parallel combinations.

ii. The advantages of parallel combination are as follows: 

1) The functioning of the other lamps is not affected if one lamp is broken. 

2) Due to their parallel connection, they will be utilizing the entire power of the battery.

iii. The lamp with the highest power will glow the brightest. 𝑃 = 𝑉𝐼 

In this case, all the bulbs have the same voltage. 

But lamp C has the highest current. 

Hence, for Lamp C 

𝑃 = 5 × 60 𝑊𝑎𝑡𝑡 

⇒ 𝑃 = 300𝑊 

Therefore, lamp C glows the brightest.

                                             (OR)

i. The magnetic field lines produced are into the plane of the paper at R and out of it at S.

ii. 𝐹𝑖𝑒𝑙𝑑 𝑎𝑡 𝑆 > 𝐹𝑖𝑒𝑙𝑑 𝑎𝑡 𝑃 

For a straight conductor carrying current, the magnetic field strength is inversely proportional to the distance from the wire.

iii. The magnetic field lines are now in a clockwise direction on a plane that is perpendicular to the wire carrying current, and the current will be flowing in the wire shown from top to bottom.

iv. The right-hand thumb rule is used to find the direction of the magnetic field for a straight current-carrying conductor. ‘The thumb is aligned to the direction of the current, and the direction in which the fingers are wrapped around the wire will give the direction of the magnetic field.’