Electricity AS

Kirchoff's First Law states

• the sum of the currents entering any junction in an electric circuit must equal the sum of the currents leaving that junction

• the sum of the charges entering any junction in an electric circuit must equal the sum of the charges leaving that junction

• the sum of the emfs entering any junction in an electric circuit must equal the sum of the pds leaving that junction

• none of these

Select all true statements

• Kirchoff's second law depends on the conservation of energy principle

• Kirchoff's first law depends upon the conservation of charge

• Kirchoff's second law depends on the conservation of charge principle

• Kirchoff's first law depends upon the conservation of energy

• i1 + i5 +i4 = i2 + i3

• i1 + i5 +i3 = i2 + i4

• i5 + i2 +i4 = i1 + i3

• i1 + i5 = i2 + i3 + i4

Which equations are correct?

• ε₁ - i₁R₁ - i₂R₂ = 0

• ε_{1 +} ε₂ + i₃R₃ - i₂R₂ = 0

• ε₁ - i₂R₁ - i₂R₂ = 0

• ε₁ - ε₂ - i₃R₃ + i₂R₂ = 0

If three 1.5 V cells are connected in series

• the combined emf is 4.5 V and it will last as long as a single 1.5 V cell

• the combined emf is 1.5 V and it will last as long as a single 1.5 V cell

• the combined emf is 4.5 V and it will last longer than a single 1.5 V cell

• none of these

If three 1.5 V cells are connected in parallel

• the combined emf is 4.5 V and it will last as long as a single 1.5 V cell

• the combined emf is 1.5 V and it will last longer than a single 1.5 V cell

• the combined emf is 4.5 V and it will last as long as a single 1.5 V cell

• none of these

Two 4000 Ω are connected in parallel, and then these are connected in series to another pair of parallel wired resistors to give a total circuit resistance of 6000 Ω. What are the possible values of the other pair?

• both 8000 Ω

• both 4000 Ω

• one 5500 Ω and the other 8000 Ω

• one 6000 Ω and the other 12000 Ω

Which statement about parallel circuits is correct?

• The current flowing through each loop is always the same

• The potential difference across each loop is always the same

• The resistance of each loop is always the same

25 C of charge transfers 50 J of energy between two points. What is the potential difference between those points?

• 2 V
• 1 V
• 3 V
• 5 V

Lydia is comparing series and parallel circuits in a class practical. Lydia switches on both circuits. Which one is correct?

• The reading on A₁ is less than the reading on A₂.

• The total resistance in circuit B is 6 Ω.

• The p.d. across the 8 Ω is the same in both circuits.

• The p.d. across A₂ is very large