# Physics equations/22-Magnetism/Q:forces

## a22Magnetism_forces_v1

A cosmic ray alpha particle encounters Earth's magnetic field at right angles to a field of 5.7 μT. The kinetic energy is 361 keV. What is the radius of particle's orbit?

 a) 1.5 x 102 m. b) 4.8 x 102 m. c) 1.5 x 103 m. d) 4.8 x 103 m. e) 1.5 x 104 m.

copies
```===2===
{<!--a22Magnetism_forces_1-->A cosmic ray alpha particle encounters Earth's magnetic field at right angles to a field of 11.4 μT.  The kinetic energy is 307 keV.  What is the radius of particle's orbit?}
-a) 7 x 10<sup>1</sup> m.
-b) 2.2 x 10<sup>2</sup> m.
-c) 7 x 10<sup>2</sup> m.
-d) 2.2 x 10<sup>3</sup> m.
+e) 7 x 10<sup>3</sup> m.
===3===
{<!--a22Magnetism_forces_1-->A cosmic ray alpha particle encounters Earth's magnetic field at right angles to a field of 7.4 μT.  The kinetic energy is 437 keV.  What is the radius of particle's orbit?}
-a) 1.3 x 10<sup>2</sup> m.
-b) 4.1 x 10<sup>2</sup> m.
-c) 1.3 x 10<sup>3</sup> m.
-d) 4.1 x 10<sup>3</sup> m.
+e) 1.3 x 10<sup>4</sup> m.
```

## a22Magnetism_forces_v1

Two parallel wires are 7.2 meters long, and are separated by 6.9 mm. What is the force if both wires carry a current of 13.7 amps?

 a) 1.24 x 10-2 newtons b) 3.92 x 10-2 newtons c) 1.24 x 10-1 newtons d) 3.92 x 10-1 newtons e) 1.24 x 100 newtons

copies
```===2===
{<!--a22Magnetism_forces_2-->Two parallel wires are 6.7 meters long, and are separated by 5.7 mm.  What is the force if both wires carry a current of 13.3 amps?}
-a) 4.16 x 10<sup>-4</sup> newtons
-b) 1.32 x 10<sup>-3</sup> newtons
-c) 4.16 x 10<sup>-3</sup> newtons
-d) 1.32 x 10<sup>-2</sup> newtons
+e) 4.16 x 10<sup>-2</sup> newtons
===3===
{<!--a22Magnetism_forces_2-->Two parallel wires are 7.5 meters long, and are separated by 4.4 mm.  What is the force if both wires carry a current of 14.8 amps?}
-a) 2.36 x 10<sup>-3</sup> newtons
-b) 7.47 x 10<sup>-3</sup> newtons
-c) 2.36 x 10<sup>-2</sup> newtons
+d) 7.47 x 10<sup>-2</sup> newtons
-e) 2.36 x 10<sup>-1</sup> newtons
```

## a22Magnetism_forces_v1

Blood is flowing at an average rate of 21.5 cm/s in an artery that has an inner diameter of 3.5 mm. What is the voltage across a hall probe placed across the inner diameter of the artery if the perpendicular magnetic field is 0.11 Tesla?

 a) 8.28 x 10-6 Volts b) 2.62 x 10-5 Volts c) 8.28 x 10-5 Volts d) 2.62 x 10-4 Volts e) 8.28 x 10-4 Volts

copies
```===2===
{<!--a22Magnetism_forces_3-->Blood is flowing at an average rate of  20.5 cm/s in an artery that has an inner diameter of 4.5 mm.  What is the voltage across a hall probe placed across the inner diameter of the artery if the perpendicular magnetic field is 0.12 Tesla?}
-a) 3.5 x 10<sup>-5</sup> Volts
+b) 1.11 x 10<sup>-4</sup> Volts
-c) 3.5 x 10<sup>-4</sup> Volts
-d) 1.11 x 10<sup>-3</sup> Volts
-e) 3.5 x 10<sup>-3</sup> Volts
===3===
{<!--a22Magnetism_forces_3-->Blood is flowing at an average rate of  24.5 cm/s in an artery that has an inner diameter of 3.9 mm.  What is the voltage across a hall probe placed across the inner diameter of the artery if the perpendicular magnetic field is 0.17 Tesla?}
-a) 5.14 x 10<sup>-5</sup> Volts
+b) 1.62 x 10<sup>-4</sup> Volts
-c) 5.14 x 10<sup>-4</sup> Volts
-d) 1.62 x 10<sup>-3</sup> Volts
-e) 5.14 x 10<sup>-3</sup> Volts
```

## a22Magnetism_forces_v1

An electron tube on Earth's surface is oriented horizontally towards magnetic north. The electron is traveling at 0.07c, and Earth's magnetic field makes an angle of 22.5 degrees with respect to the horizontal. To counter the magnetic force, a voltage is applied between two large parallel plates that are 54 mm apart. What must be the applied voltage if the magnetic field is 45μT?

 a) 2 x 10-1 volts b) 6.2 x 10-1 volts c) 2 x 100 volts d) 6.2 x 100 volts e) 2 x 101 volts

copies
```===2===
{<!--a22Magnetism_forces_4-->An electron tube on Earth's surface is oriented horizontally towards magnetic north.  The electron is traveling at 0.07c, and Earth's magnetic field makes an angle of 47.5 degrees with respect to the horizontal.  To counter the magnetic force, a voltage is applied between two large parallel plates that are 57  mm apart.  What must be the applied voltage if the magnetic field is 46μT?}
-a) 4.1 x 10<sup>0</sup> volts
-b) 1.3 x 10<sup>1</sup> volts
+c) 4.1 x 10<sup>1</sup> volts
-d) 1.3 x 10<sup>2</sup> volts
-e) 4.1 x 10<sup>2</sup> volts
===3===
{<!--a22Magnetism_forces_4-->An electron tube on Earth's surface is oriented horizontally towards magnetic north.  The electron is traveling at 0.06c, and Earth's magnetic field makes an angle of 48.5 degrees with respect to the horizontal.  To counter the magnetic force, a voltage is applied between two large parallel plates that are 59  mm apart.  What must be the applied voltage if the magnetic field is 45μT?}
-a) 1.1 x 10<sup>0</sup> volts
-b) 3.6 x 10<sup>0</sup> volts
-c) 1.1 x 10<sup>1</sup> volts
+d) 3.6 x 10<sup>1</sup> volts
-e) 1.1 x 10<sup>2</sup> volts
```