Explanation :
It is given that,
Diameter of the coil, d = 20 cm = 0.2 m
Radius of the coil, r = 0.1 m
Number of turns, N = 3000
Induced EMF, 
Magnitude of Earth's field, 
We need to find the angular frequency with which it is rotated. The induced emf due to rotation is given by :




So, the angular frequency with which the loop is rotated is 159.15 rad/s. Hence, this is the required solution.
Answer:
Speed of the speeder will be 28 m/sec
Explanation:
In first case police car is traveling with a speed of 90 km/hr
We can change 90 km/hr in m/sec
So 
Car is traveling for 1 sec with a constant speed so distance traveled in 1 sec = 25×1 = 25 m
After that car is accelerating with
for 7 sec
So distance traveled by car in these 7 sec

So total distance traveled by police car = 224 m
This distance is also same for speeder
Now let speeder is moving with constant velocity v
so 
v = 28 m/sec
Explanation:
Though the diagram that is mentioned in the questions is not given. I have given general information related to the Earth's magnetic axis with respect to geographic/rotational axis.
Axis is an imaginary line around which a body rotates. The rotational axis of the Earth enters into and exits from the Earth at two points namely: North and South pole.
We know that the Earth behaves like a huge bar magnet so just like the bar magnet it must also have magnetic axis and poles. Earth has north magnetic pole and south magnetic pole. It has a strong magnetic field as well known as magnetosphere.
The interesting point about magnetic axis is that it is not same as rotational axis. In fact it makes an angle with the rotational axis. This is known as magnetic inclination. This inclination varies at different points on Earth.
Another interesting point is that the geographic and magnetic poles are opposite. That means near the geographic north pole we have the magnetic south pole and vice versa.
Answer:
the charge that is given by the object is positive charge and the object which is taking the charge is negetively charged
Explanation:
D. All of the above
At high tide fish will feed among the mangrove roots - rich fishing ground
The trees trap sediment and soil in the river that would flow out to sea which also helps stop erosion
Wildlife utilise almost every part of the tree, with insects and birds, monkeys and lizards in the branches, shrimps and fish in the roots, and snails and clams in the soil