(i) Two 110V lamps are connected in parallel. Their ratings are 150W and 200W.

Physics

1 answer:

LekaFEV [45]3 years ago

7 0

Answer:

37.7 Ω

Explanation:

The resistance in each lamp is:

P = IV = V²/R

R = V²/P

R₁ = (110 V)² / (150 W)

R₁ = 80.67 Ω

R₂ = (110 V)² / (200 W)

R₂ = 60.5 Ω

Their combined resistance in parallel is:

1/R = 1/R₁ + 1/R₂

1/R = 1/(80.67 Ω) + 1/(60.5 Ω)

R = 34.57 Ω

So the current that goes through them is:

V = IR

I = V/R

I = (110 V) / (34.57 Ω)

I = 3.182 A

We need the same current in the new circuit.

V = IR

230 V = (3.182 A) (R₃ + 34.57 Ω)

R₃ = 37.7 Ω

We can check our answer by finding the voltage drop across this resistor:

V = I R₃

V = (3.182 A) (37.7 Ω)

V = 120 V

230 V − 120 V = 110 V, the correct voltage for the lamps.

You might be interested in

For an increase in the bulk modulus of a material but without any change in the density, what happens to the speed of sound in t

vazorg [7]

The speed of sound, c, is given by the Newton-Laplace formula
$c = \sqrt{ \frac{K}{\rho} }$
where
K = bulk modulus
ρ = density

Because the density is constant, the speed of sound is proportional to the square root of the bulk modulus.

Therefore when the bulk modulus increases, the speed of sound increases by the square root of the bulk modulus.

For example, if K is doubled, then
$c = \sqrt{2K} = \sqrt{2} \sqrt{K}$

Answer:
If the bulk modulus increases by a factor of n, then c increases by a factor of √n.

7 0

3 years ago

State two factors that affect the type of Shadows formed

Vadim26 [7]

Answer:

The two factors that affect the type of Shadows formed are stated below ::