Answer:
Explanation:
When a wire of length L is moved with velocity v , perpendicular to magnetic field B , EMF will be produced at its two ends . EMF can be calculated with the help of following expression
EMF = BLv
As per this formula , EMF produced will not depend upon number of electrons in the magnetic field.
So B is the right choice.
Answer:
The speed of washer will be 32.144 m/s
Explanation:
Given that
time t= 3.28 s
Acceleration due to gravity

Here acceleration is constant so we cam apply the motion equation
we know that
v= u + at
At initial condition u =0 m/s
v= u + at
v= 0 + 9.8 x 3.28
v= 32.144 m/s
So the speed of washer will be 32.144 m/s
Here in the process we require
1. Heat to melt down all ice
2. Heat to raise the temperature of whole water to 100 degree C
3. Heat to boil off the water
now here for the first part
Heat required to melt the ice


now heat required to raise the temperature to 100 degree C



Now heat required to boil it off


now the total heat required will be



so it required 287200 calorie heat to boil it all water
-- "Declination zero" means the object is in the sky at some point directly over the Earth's equator.
-- If it's the sun and it appears to be over the equator, then that tells us that the Earth's axis is not tilted toward or away from it.
-- That in turn tells us that the Earth is at one of the two equinoxes in its orbit, either the Spring one or the Autumn one. <em> (D)</em>
-- (The first days of Summer and Winter coincide with solstices, not equinoxes.)
Answer:
a) 4.65m/s
b) 59.8 N , 1.01125 N
Explanation:
a)
m = mass of the ball = 1 kg
r = length of the string = 2.0 m
h = height gained by the ball as it moves from lowest to topmost position = 2r = 2 x 2 = 4 m
v = speed at the lowest position = 10 m/s
v' = speed at the topmost position = ?
Using conservation of energy
Kinetic energy at topmost position + Potential energy at topmost position = Kinetic energy at lowest position
(0.5) m v'² + m g h = (0.5) m v²
(0.5) v'² + g h = (0.5) v²
(0.5) v'² + (9.8 x 4) = (0.5) (10)²
v' = 4.65m/s
b)
T' = Tension force in the string when the ball is at topmost position
T = Tension force in the string when the ball is at lowest position
At the topmost position:
force equation is given as


T' = 1.01125 N
At the lowest position:
force equation is given as


T = 59.8 N