Answer:
<em>P = 66.67 W</em>
Explanation:
<u>Joule Heating</u>
It's the process by which the electric current passing through a conductor produces heat.
Also known as Joule's first law or the Joule–Lenz law, states that the power of heating generated by an electrical conductor (P) is proportional to the product of its resistance (R) and the square of the current (I).
It can be described by the equation that follows:
Also, we can calculate the voltage V with the formula of Ohm's law:
Combining both equations, power can be related to the voltage:
Given the power and the voltage, the resistance can be calculated by solving for R:
There are two bulbs marked P=200W V=250V and P=100 W V=250.
The first bulb has a resistance of:
The first bulb has a resistance of:
When connected in series, the total resistance is
The total power consumed when connecting them to a V=250 V supply is:
P = 66.67 W
Answer:
2.85 s .
Explanation:
y(t) = y(0) + v₀t + 1/2 gt²
y(t) is vertical displacement , y(0) is initial position , v₀ is initial velocity and t is time required to make vertical displacement and g is acceleration due to gravity.
Here y(0) is zero , v₀ = 14 m/s , g = 9.8 m s⁻² , y(t ) = 0 , as the pumpkin after time t comes back to its initial position, that is ground .
We shall take v₀ as negative as it is in upward direction and g as positive as it acts in downward direction
Put the values in the equation above,
0 = 0 - 14t + 1/2 x 9.8 t²
14 t = 1/2 x 9.8 t²
t = 28 / 9.8
t = 2.85 s .
Answer:
option C
Explanation:
given,
energy dissipated by the system to the surrounding = 12 J
Work done on the system = 28 J
change in internal energy of the system
Δ U = Q - W
system losses energy = - 12 J
work done = -28 J
Δ U = Q - W
Δ U = -12 -(-28)
Δ U = 16 J
hence, the correct answer is option C
Answer:
2. +0.2 C
Explanation:
When the two spheres touch, the total charge will be redistributed such that the two spheres are at same potential:
The potential can be rewritten as ratio between the charge on the sphere (Q) and the capacitance of the sphere (C):
Since the two spheres are identical, they have same capacitance:
So we can write
And since the total charge is
And this charge will be redistributed equally on the two spheres (
), we have
<span>The
answer is towards <span>the poles. This is because, at
the poles of the magnet, the magnetic field lines get closer together hence
indicating that the magnetic force is stronger here. The fields are closest
together at the center of the magnet and farthest at the outside side of the
magnet. </span></span>
