# Solving Part B of Homework Equation | Φ, EMF & V

• Samurai44
In summary, the conversation is about calculating the electromagnetic force (emf) using the formula Φ=NBA. The person found the area and calculated Φ, but was confused about how to find the emf using the derivative of Φ with respect to time. The other person clarified that the step from Φ to emf involves using the derivative, and the person understood that they needed to use dΦ/dt. The conversation then shifts to discussing the area with a magnetic field and how it changes over time as the coil moves. The concept of speed and distance covered over time is also mentioned.
Samurai44

## Homework Statement

Uploaded the question below , Part B

## Homework Equations

Φ=NBA
EMF= (delta)Φ/(delta)t
V=IR

## The Attempt at a Solution

so i found the area (0.25x0.3) and then divided by two (=0.0375m^2) , then found Φ=80x1.4x0.0375=4.2wb
However , in the marking scheme they multiplayed by the speed instead of area !

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So, you calculated ##\Phi##. But for the emf you need ##d\Phi\over dt##. Is the step from one to the other unclear to you ?

BvU said:
So, you calculated ##\Phi##. But for the emf you need ##d\Phi\over dt##. Is the step from one to the other unclear to you ?
i know i have to use dΦ/dt , that's why i calculated Φ .. couldn't get how they found 0.7v

Area with magnetic field within the loop is xy . x is constant, 0.25 m. At t=0 y = 0.15 m . When the coil is moving, y decreases by 2 m/s

BvU said:
Area with magnetic field within the loop is xy . x is constant, 0.25 m. At t=0 y = 0.15 m . When the coil is moving, y decreases by 2 m/s
so its like we make change of "y" over time equals to the speed ? since speed = distance covered / time taken

That is exactly what it is !

## What is Φ, EMF, and V in relation to solving Part B of the Homework Equation?

Φ, EMF, and V are all components of the Homework Equation, which is used to solve problems related to circuits and electromagnetic fields. Φ represents the magnetic flux, EMF represents the electromotive force, and V represents the potential difference.

## How do I determine the value of Φ, EMF, or V in the Homework Equation?

The value of Φ, EMF, or V can be determined by using the appropriate formulas and plugging in the known values for other components in the equation. For example, to find the value of V, you would use the formula V = IR, where I represents the current and R represents the resistance.

## What is the relationship between Φ, EMF, and V in the Homework Equation?

In the Homework Equation, Φ, EMF, and V are all related to each other through the laws of electromagnetism. Φ is directly proportional to EMF and inversely proportional to V. This means that an increase in Φ will result in an increase in EMF and a decrease in V.

## Can the Homework Equation be used to solve problems in different areas of science?

Yes, the principles behind the Homework Equation can be applied to various fields such as physics, engineering, and chemistry. However, the specific formulas and values used may vary depending on the specific problem being solved.

## What are some common mistakes to avoid when using the Homework Equation to solve Part B of a homework problem?

Some common mistakes to avoid include using incorrect units, not considering the direction of current and magnetic field, and not taking into account the sign conventions for EMF and V. It is important to carefully read and understand the problem and double check all calculations to avoid these errors.

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