R_t is resistance at changed temperature , Ro is resistance at initial temperature , α is temperature coefficient of resistivity . t is temperature change .

For iron , R₀ = 10 , α = 5 x 10⁻³ , t = - 100 degree

R_t = 10( 1 + 5 x 10⁻³ x - 100 )

= 10( 1 - 5 x 10⁻³ x 100 )

10 x ( 1 - .5 )

10 x .5

For carbon

, R₀ = 10 , α = - 0.5 x 10⁻³ , t = - 100 degree

R_t = 10( 1 - 0. 5 x 10⁻³ x - 100 )

= 10( 1 + .5 x 10⁻³ x 100 )

10 x ( 1 + .05 )

10 x 1.05

Required ratio

= 10 x 1.05 / 10 x .5

= 105 / 50

= 21 / 10

= 2.1

3 0

3 years ago

For a certain RLC circuit the maximum generator EMF is 125 V and the maximum current is 3.20 A. If le a) the impedance of the ci

MAXImum [283]

Answer:

Part (i)

Z = 39.06 ohm

Part (ii)

R = 21.7 ohm

Explanation:

a) here we know that

maximum value of EMF = 125 V

maximum value of current = 3.20 A

now by ohm's law we can find the impedence as

$z = \frac{V_o}{i_o}$

now we will have

$z = \frac{125}{3.20} = 39.06 ohm$

Part b)

Now we also know that

$\frac{R}{z} = cos\theta$

$\theta = 0.982 rad = 56.3 degree$

now we have

$\frac{R}{39.06} = cos56.3$

$R = 21.7 ohm$

5 0

4 years ago