A straight horizontal rod x, of mass 50g and length 0.5m ,is placed in a uniform field of0.2T perpendicular to x. Calculate the current in x if the force acting on it just balances it weight.

No

To calculate the current in the rod (x) when the force acting on it balances its weight, you can use the equation for the force on a current-carrying conductor in a magnetic field.

The force (F) on a current-carrying conductor in a magnetic field is given by the equation:

F = BIL

Where:
F is the force on the conductor,
B is the magnetic field strength,
I is the current flowing through the conductor, and
L is the length of the conductor.

In this case, the force acting on the rod is equal to its weight:

F = mg

Where:
F is the force,
m is the mass of the rod, and
g is the acceleration due to gravity.

Since the force acting on the rod in the magnetic field balances its weight, we can equate the two forces:

mg = BIL

Rearranging the equation, we can solve for the current (I):

I = (mg) / (BL)

Now, let's substitute the given values:

m = 50 g = 0.050 kg (convert grams to kilograms)
g = 9.8 m/s^2 (acceleration due to gravity)
B = 0.2 T (magnetic field strength)
L = 0.5 m (length of the rod)

I = (0.050 kg × 9.8 m/s^2) / (0.2 T × 0.5 m)

By simplifying the equation:

I = 0.980 A

Therefore, the current in the rod (x) is 0.980 Amperes.