Answer:
R = 2481 Ω
L= 1.67 H
Explanation:
(a) We have an inductor L which has an internal resistance of R. The inductor is connected to a battery with an emf of E = 12.0 V. So this circuit is equivalent to a simple RL circuit. It is given that the current is 4.86 mA at 0.725 ms after the connection is completed and is 6.45 mA after a long time. First we need to find the resistance of the inductor. The current flowing in an RL circuit is given by
i = E/R(1 -e^(-R/L)*t) (1)
at t --> ∞ the current is the maximum, that is,
i_max = E/R
solve for R and substitute to get,
R= E/i_max
R = 2481 Ω
(b) To find the inductance we will use i(t = 0.940 ms) = 4.86 mA, solve (1) for L as,
Rt/L = - In (1 - i/i_max
)
Or,
L = - Rt/In (1 - i/i_max
)
substitute with the givens to get,
L = -(2481 Si) (9.40 x 10-4 s)/ In (1 - 4.86/6.45
)
L= 1.67 H
<u><em>note :</em></u>
<u><em>error maybe in calculation but method is correct</em></u>
Answer:
The rotational kinetic energy of the hoop and the instantaneous change rate of the kinetic energy are 2.25 J and 15 J.
Explanation:
Given that,
Mass = 2 kg
Radius = 0.5 m
Angular speed = 3 rad/s
Force = 10 N
(I). We need to calculate the rotational kinetic energy
Using formula of kinetic energy
(II). We need to calculate the instantaneous change rate of the kinetic energy
Using formula of kinetic energy
On differentiating
....(I)
Using newton's second law
Put the value of a in equation (I)
Hence, The rotational kinetic energy of the hoop and the instantaneous change rate of the kinetic energy are 2.25 J and 15 J.
Answer:
Explanation:
1 cm =10mm so 800cm is equal to 8000mm.so b is the correct answer
Answer:
Explanation:
100 W bulb is using energy of 100 J in one second.
22 percent of the electrical energy is transformed to radiant energy.
a )
So , electrical energy is transformed to radiant energy per second
= 100 x .22 = 22 J
energy transformed in one minute = 22 x 60 J
= 1320 J
b )
electrical energy is transformed to heat energy per second
= 100 x .78 = 78 J
energy transformed in one minute = 78 x 60 J
= 4680 J