it become easier to carry a load in a wheel barrow when the load is shift towards its wheel give reason

In a photoelectric experiment it is found that a stopping potential of 1.00 V is needed to stop all the electrons when incident

kiruha [24]

Answer:

Planck’s constant is $6.9*10^{-34} Js$

work function of metal is $5.846*10^{-19}$

Explanation:

The maximum kinetic energy from electron from photoelectric effect is given by

$\K_{max}=eV_o$ where $V_o$ is applied voltage and e is charge on electron and substituting charge on electron by $1.6*10^{-19}$ and 1.00 V for $V_o$

$K_{max}=1.6*10^{-19}*1=1.6*10^{-19} J$

Considering that the wavelength, \lambda of light used is given as $278*10^{-9} m$

Energy of light is given by

$E=\frac {hc}{ \lambda}$ where $\lambda$ is the wavelength, h is Planck’s constant and c is speed of light. Taking c for $3*10^{8} m/s$

Substituting values of wavelength and speed of light we obtain

$E=\frac {h*3*10^{8}}{278*10^{-9}}=h1.07914*10^{15} J$

If work function is $\phi$ then

$E=\phi + k_{max}$ hence

$h1.07914*10^{15} J=\phi +1.6*10^{-19} J$ ------- Equation 1

Energy corresponding to wavelength of 207 nm is

$E=h\frac {3*10^{8} m/s}{207*10^{-9}}=h(1.45*10^{15}}) J$

Maximum kinetic energy of electrons when $V_o$ is 2.6 V becomes

$K_{max}=(1.6*10^{-19})*2.6V=4.16*10^{-19} J$

From $E=\phi + k_{max}$ and substituting $h(1.45*10^{15}}) J$ for E and $4.16*10^{-19} J$ for $K_{max}$ we have

$h(1.45*10^{15}}) J=\phi +4.16*10^{-19} J$ ------ Equation 2

Equation 2 minus equation 1 gives

$h3.71*10^{14}=2.56*10^{-19}$

$h=\frac {2.56*10^{-19}}{3.71*10^{14}}\approx 6.9*10^{-34} Js$

Therefore, Planck’s constant is $6.9*10^{-34} Js$

Recalling equation 1 and substituting back the value of h as obtained

$h1.07914*10^{15} J=\phi +1.6*10^{-19} J$

$(6.9*10^{-34})*(1.07914*10^{15})=\phi +1.6*10^{-19} J$

$\ph=(6.9*10^{-34})*(1.07914*10^{15})-(1.6*10^{-19})=5.846*10^{-19}$

Therefore, work function of metal is $5.846*10^{-19}$

5 0

4 years ago

A factor that does not change in an experiment is the

quester [9]

Answer:

independent variable

Explanation:

5 0

4 years ago

Read 2 more answers

What does it mean for forces to be in equilibrium?.

lapo4ka [179]

Explanation:

If the size and direction of the forces on the object are exactly balanced , then there is no net force acting on the object

8 0

3 years ago

An elevator is moving downward when someone presses the emergency stop button. The elevator comes to rest a short time later. Gi

OLga [1]

Answer:

<em>Answer: - , + </em>

Explanation:

<u>Velocity and Acceleration </u>

In general terms, velocity and acceleration in the plane are both vectors with two components. They don't have 'sign' but magnitude and direction. If we know motion is restricted to a simple line, then we can define the positive and negative references.

In vertical motion, the positive reference is commonly pointed upwards, but if we chose the opposite way, the results shouldn't change in magnitude, just their signs. Let's choose like proposed, the positive direction upwards.

Since the elevator was moving downwards, its velocity is negative. When the button is pushed, it continues to move downwards, but slower. Its velocity is still negative.

The acceleration has the same sign as the velocity if it tends to increase the magnitude of the object, and is negative in the opposite case. Let's look at the formula

$\displaystyle a=\frac{v_f-v_o}{t}$