जब कोई आवेशित कण एकसमान चुंबकीय क्षेत्र में गति करता है, तो निम्नलिखित में से कौन सी राशि अपरिवर्तित रहती है?

Consider two wire arrangements carrying equal current I: Arrangement 1 consists of a semi-circular arc of radius R and two straight infinite wire segments extending along its tangent. Arrangement 2 consists of a semi-circular arc of radius R with two radial straight wires extending to infinity. The ratio of the magnetic field at the center of the semi-circular part in Arrangement 1 to that in Arrangement 2 is:

The magnetic field produced inside a long current-carrying solenoid is: