Two ends of a horizontal conducting rod of length l are joined to a vo...
Explanation:
When a conductor moves in a magnetic field, an electric field is induced in the conductor due to the magnetic force acting on the moving charges. This induced electric field creates a potential difference (voltage) across the conductor, which can be measured using a voltmeter.
Direction of Motion:
In this scenario, the conducting rod is moving horizontally with a velocity v. The direction of motion is perpendicular to the rod. We need to determine the reading on the voltmeter in this situation.
Magnetic Field:
The vertical component of the Earth's magnetic field is B. This means that the magnetic field lines are oriented vertically upwards or downwards.
Induced Electric Field:
When the rod moves through the magnetic field, the moving charges experience a magnetic force perpendicular to both the velocity and the magnetic field. This force causes the charges to accumulate at the ends of the rod, creating a potential difference (voltage) across the rod.
Direction of Induced Electric Field:
The direction of the induced electric field can be determined using Fleming's right-hand rule. According to this rule, if we point our thumb in the direction of the velocity (eastward in this case) and our fingers in the direction of the magnetic field (upwards or downwards), then the direction in which the palm faces gives the direction of the induced electric field.
Reading on the Voltmeter:
Since the ends of the rod are connected to the voltmeter, the voltmeter measures the potential difference across the rod. This potential difference is equal to the product of the induced electric field and the length of the rod (V = E × l).
Conclusion:
From the above analysis, we can conclude that the voltmeter will read Blv if the rod moves in any direction. This is because the induced electric field is always perpendicular to the velocity of the rod and the magnetic field. The length of the rod does not affect the reading on the voltmeter, as long as the rod is moving through the magnetic field.