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Find the magnitude of the force on an electron that is travelling with velocity 2 x 10^4 ms^(-1) in the x direction through a uniform magnetic field of strength 2T in the y direction.

This question tells us we only need to consider the magnitude of the force, and since the magnetic field and electron's velocity are perpendicular, we can simply use the equation

Answered by Sally H. • Physics tutor

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What is viscosity?

Viscosity is a measure of a fluid's resistance to flow. It describes the internal friction of a moving fluid. A fluid with large viscosity resists motion because its molecular makeup give...

Answered by Juan N. • Physics tutor

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A capacitor discharge circuit of time constant 45ms includes a capacitor and resistor. The capacitor has a capacitance of 18µF What is the resistance of the resistor?

This question is in one of the CIE Physics Pre-U sample papers, and if you know the definition of the time constant for a capacitor circuit (=RC), its very easy, however even if you didnt it canbe deri...

Answered by Sam C. • Physics tutor

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What determines the acoustic impedance of a material and why is it useful in understanding ultrasound imaging?

Acoustic impedance is the density of a material multiplied by the speed of sound in the material.
Knowing these two values allows use to calculate how much of th...

Answered by David A. • Physics tutor

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How is a piezoelectric crystal used to generate waves of ultrasound?

A piezoelectric crystal makes use of the peizoelectric effect. This is the production of a voltage when mechanical stress is applied across the material. This occurs only in materials ...

Answered by David A. • Physics tutor

9255 Views