Light Emitting Diode

Q. Current flowing in a Zener diode as shown in circuit is:

(Given diode is an ideal and $V_Z=4\text{V})$

1. $0.9\text{A}$
2. $0.1\text{A}$
3. $0.4\text{A}$
4. $0.5\text{A}$

Q. Light Emitting Diode is a forward biased p-n junction diode.

1. False
2. True

Q. A beam of light consisting of two wavelengths $420\text{nm}$ and $540\text{nm}$ falls on two metals $1$ and $2$ of work functions $4.0\text{eV}$ and $2.5\text{eV}$ respectively. If the intensities of the two wavelengths are equal, which of the graphs shown in figure represents the variation of photoelectric current $\left(i\right)$ with voltage $\left(V\right)$ is correct?
[Take $hc=1240\text{eV (nm)}$ ]

1. 
2. 
3. 
4. 

Q. A laser beam has intensity $2.5\times {10}^{14}$${\text{Wm}}^{-2}$. The amplitudes of electric and magnetic fields in the beam are :

1. $1.44\times {10}^8\text{N/C},4.34\text{T}$
2. $4.34\times {10}^8\text{N/C},1.44\text{T}$
3. $4.34\text{N/C},1.44\text{T}$
4. $4.34\times {10}^8\text{N/C},1.44\times {10}^{-2}\text{T}$

Q. Current flowing in a Zener diode as shown in circuit is:

(Given diode is an ideal and $V_Z=4\text{V})$

1. $0.9\text{A}$
2. $0.1\text{A}$
3. $0.4\text{A}$
4. $0.5\text{A}$