What is energy?

A Hall probe, consisting of a rectangular slab of current-carrying material, is calibrated by placing it in a known magnetic fie

Citrus2011 [14]

Answer:

(a) 0.345 T

(b) 0.389 T

Solution:

As per the question:

Hall emf, $V_{Hall} = 20\ mV = 0.02\ V$

Magnetic Field, B = 0.10 T

Hall emf, $V'_{Hall} = 69\ mV = 0.069\ V$

Now,

Drift velocity, $v_{d} = \frac{V_{Hall}}{B}$

$v_{d} = \frac{0.02}{0.10} = 0.2\ m/s$

Now, the expression for the electric field is given by:

$E_{Hall} = Bv_{d}sin\theta$ (1)

And

$E_{Hall} = V_{Hall}d$

Thus eqn (1) becomes

$V_{Hall}d = dBv_{d}sin\theta$

where

d = distance

$B = \frac{V_{Hall}}{v_{d}sin\theta}$ (2)

(a) When $\theta = 90^{\circ}$

$B = \frac{0.069}{0.2\times sin90} = 0.345\ T$

(b) When $\theta = 60^{\circ}$

$B = \frac{0.069}{0.2\times sin60} = 0.398\ T$

5 0

2 years ago

Two wheels having the same radius and mass rotate at the same angular velocity ((Figure 1) ). One wheel is made with spokes so n

liubo4ka [24]

Answer:

E. The wheel with spokes has about twice the KE.

See explanation in: https://quizlet.com/100717504/physics-8-mc-flash-cards/

6 0

3 years ago

Read 2 more answers

Countries with traditional economies are often less developed because:

3241004551 [841]

People are resistant to change, People have political freedom, Farmers institute new farming techniques and there is little need for medical facilities.

7 0

2 years ago

Read 2 more answers

Select the phrases that correctly describe density. Density is a chemical property. Density relates a mass to its volume. Densit

sp2606 [1]

Answer:

Density relates a mass to its volume.

Density varies with temperature

Density determines if a substance floats or sinks.

Density may have units of grams per milliliter (g/mL)

Explanation:

Density $D$ is a characteristic property of a substance or material and is defined as the relationship between the mass $m$ of a body or substance and the volume $V$ it occupies:

$D=\frac{m}{V}$

This means the density is inversely proportional to the volume.

On the other hand, density is a scalar quantity and according to the International System of Units its unit is $D=\frac{kg}{m^{3}}$ , although it can be also expressed in $\frac{g}{ml}$ .

It should be noted that the density of a body is related to its buoyancy, a substance or body will float on another fluid if its density is lower. In addition, if the pressure of the substance remains constant, as the temperature increases, the density decreases; this means density varies with the temperature as well.

5 0

2 years ago

During a very quick stop, a car decelerates at 7.6 m/s2. Assume the forward motion of the car corresponds to a positive directio

Mashcka [7]

Answer:

24.57 revolutions

Explanation:

(a) If they do not slip on the pavement, then the angular acceleration is

$\alpha = a / r = 7.6 / 0.26 = 29.23 rad/s^2$

(b) We can use the following equation of motion to find out the angle traveled by the wheel before coming to rest:

$\omega^2 - \omega_0^2 = 2\alpha\Delta \theta$

where v = 0 m/s is the final angular velocity of the wheel when it stops, $\omega_0$ = 95rad/s is the initial angular velocity of the wheel, $\alpha = -29.23 rad/s^2$ is the deceleration of the wheel, and $\Delta \theta$ is the angle swept in rad, which we care looking for:

$0 - 95^2 = 2*29.23\Delta \theta$

$9025 = 58.46 \Delta \theta$

$\Delta \theta = 9025 / 58.46 = 154.375 rad$

As each revolution equals to 2π, the total revolution it makes before stop is

154.375 / 2π = 24.57 revolutions

8 0

2 years ago