Physics Electromagnetic Induction Level: High School
A coil has a resistance R = 2.00 ohms and an inductance of 0.325 H . Determine the current in the coil if 120 V dc is applied to it .
Physics Electromagnetic Induction Level: High School
A square loop of wire of side 0.20 m has a total resistance of 0.60 ohm . The loop is positioned in a uniform magnetic field B of 0.030 T . The field is directed into the page , perpendicular to the plane of the loop , as shown above .a) Calculate the magnetic flux through the loop .
The field strength now increases uniformly to 0.20 T in 0.50 s.
b) Calculate the EMF induced in the loop during this period .
c)
i) Calculate the magnitude I of the current in the loop during this period .
ii) What is the direction of the current in the loop ?
d) Describe a method by which you could induce a current in the loop if the magnetic field remained constant .
Question Diagram
Physics Electromagnetic Induction Level: High School
An electrical generator contains a coil of 110 turns of wire , each forming a rectangular loop 55.7 cm by 35.3 cm . The coil is placed entirely in a uniform magnetic field with magnitude B = 3.92 T and initially perpendicular to the coil’s plane . What is in volts the maximum value of the emf produced when the loop is spun at 1310 rev/min about an axis perpendicular to the magnetic field ?
Physics Electromagnetic Induction Level: High School
A uniform magnetic field is perpendicular to the plane of a circular loop of diameter 13 cm formed from wire of diameter 1.9 mm and resistivity of 1.47 x 10^-8 ohm-m . At what rate must the magnitude of the magnetic field change to induce a 9.2 A current in the loop ?
Physics Electromagnetic Induction Level: High School
A small loop of area A = 6.8 mm^2 is inside a long solenoid that has n = 748 turns/cm and carries a sinusodally varying current I of amplitude 2.97 A and angular frequency 336 rad/s . The central axis of the loop and solenoid coincide . What is in millivolts the amplitude of the emf induced in the loop ?
Physics Electromagnetic Induction Level: High School
A 95.7 MHz FM station radiates 45 kW uniformly in all directions .a) Calculate the wavelength of the wave .
b) Calculate the intensity of the wave 35 km from the source .
c) Calculate the magnitude of the electric and magnetic fields of the waves 35 km from the source .
d) Suppose a metal sheet that will reflect 100% of the incident wave is placed perpendicular to the direction of the wave (the wave is reflected back toward the source by the sheet ) . Calculate the pressure exerted on the sheet by the wave if the sheet is 35 km from the source .
Physics Electromagnetic Induction Level: High School
A conducting loop of wire is placed in a magnetic field that is normal to the plane of the loop . Which one of the following action will not be result in an induced current in the loop ?a) Rotate the loop about an axis that is parallel to the field and passes through the centre of the loop ,
b) Increase the strength of the magnetic field .
c) Decrease the area of the loop .
d) Decrease the strength of the magnetic field .
Rotate the loop about an axis that is perpendicular to the filed and passes through the center of the loop .
Physics Electromagnetic Induction Level: High School
One method of measuring the magnetic field strength uses a closely-wound coil of wire N turns and enclosing an area A . This coil is initially placed so that the flux ¥õ through the area is a maximum (see figure at ¡°click here¡±) .Then in a small time interval . Delta t is rotated ¨ù of a turn so that it is parallel to the magnetic field , and the flux through its area reduces to zero .a) Two leads from either end of the coil are connected to a machine that measures the amount of charge Q (Q = I delta f) if the total resistance of the coil and the charge measuring device is R , derive an equation for the charge Q in terms of N,A,R and the negative flux density B .
b) A closely wound coil containing 200 turns is 45 cm in radius and has a resistance of 60.0 ohm . It is placed in a magnetic field . and connected to a charge-measuring instrument . The coil is initially perpendicular with the magnetic field , and is quickly rotated by ¨ù turn so that it becomes aligned with the field ,and a charge of 45.7 micro C is measured . What is the magnetic flux density of the field ?
Physics Electromagnetic Induction Level: High School
An engineer plans to light a train by utilizing the emf induced in the axles of the train running on the tracks .a) If the downward component of the earth’s magnetic field is 0.6 x 10^-4 T , and the tracks are 1.5 m apart , how large is the emf produced between the tracks by a train traveling at 40 m/s ?
b) Could this voltage be utilized on the moving train ?
c) Could the voltage be utilized at train station at the distant end of the tracks ?
Physics Electromagnetic Induction Level: High School
To monitor the breathing of a hospital patient , a thin belt is girded around the patient’s chest , The belt is a 200-turn coil . When the patient inhales , the area encircled by the coil increases by 39 cm^2 . The magnitude of the Earth’s magnetic field is 50 micro T and makes an angle of 28 degree with the plane of the coil .a) If a patient takes 1.8 s to inhale , find the average induced emf in the coil during this time .
Physics Electromagnetic Induction Level: High School
A 20-loop circular coil of wire radius 5 cm is placed in a magnetic field B = 2 T . When the power is turned off ,the field drops uniformly down to B = 0 in 6 seconds . During that time , what is the voltage induced in the coil ?
Physics Electromagnetic Induction Level: High School
What happens to the frequency and speed of an electromagnetic wave if its wavelength is doubled ?
Physics Electromagnetic Induction Level: High School
Earth’s Magnetism
A 2.5 m blade of a helicopter rotates at 4 rev/s . Find the vertical component of t Earth’s magnetic field if the induced emf between the tip of the blade and the central hub is 3.5 mV .
Physics Electromagnetic Induction Level: High School
The area encircled by the coil , which has 100 turns increases by 19 cm when a baby inhales . The magnitude of B field which makes an angle of 25 degree with the plane of the coil – is 0.00006 T . Assuming that the baby inhales 1.6 s . Find the magnitude of the average emf in the coil during this time .
Physics Electromagnetic Induction Level: High School
A uniform and constant (in time) magnetic field has a magnitude of 0.2 T and is perpendicular to a circular loop of wire (one turn) that has a radius of 0.3 m at t = 0 sec . At t = 0.22 s , the normal makes an angle of theta = 45 degrees with the field , because the coil has made one-eight of a revolution . Find the magnitude of the emf induced in the wire .