Кирхгоф ережесі. Физика, 10 сынып, қосымша материал 4.

 1A[1]

 2B[1]

 3B[1]

 4B[1]

 5B[1]

 6The sum of the currents into a point sum of currents out of the same point.[1]

 7aI 2.0 1.0 3.0 A[1]

b0.7 0.5 I therefore I 1.2 A[1]

c2.0 I 4.0 0.5[1]

I 4.5 2.0 2.5 A[1]

 8aE 1.5 1.5 3.0 V[1]

bE 1.5 1.5 1.5 1.5 3.0 V[1]

cE 1.5 1.5 0 V[1]

 9∑ e.m.f. ∑ p.d.[1]

6.0 (I 10) (I 20) (clockwise ‘loop’)[1]

30I 6.0 so  I 0.20 A[1]

10a∑ e.m.f. ∑ p.d.

6.0 1.5 (I 68) (I 12) (clockwise ‘loop’)[1]

80I 4.5[1]

so I [1]

bV IR 5.63 10⁻² 68 (the current is the same in a series circuit)[1]

[1]

cThe resistance of the voltmeter is infinite (or very large).[1]

11Loop 1:∑ e.m.f. ∑ p.d.

3.0 10I₁ 20I₂(equation 1)[1]

2:∑ e.m.f. ∑ p.d.

1.5 20I₂(equation 2)[1]

I₂ 0.075 A[1]

Substituting the value for I₂ into equation 1, we have:

3.0 10I₁ (20 0.075)[1]

I₁ 0.15 A[1]

Finally, using Kirchhoff’s first law, we have:

0.15 0.075 I₃

I₃ 0.075 A[1]