Semiconductor Electronics Materials Devices And Simple Circuits

The compound semiconductor used for making LEDs (Light Emitting Diodes) of different colors typically involves materials that can emit light efficiently when electrically excited.

Among the given options, the common semiconductors used for producing LEDs of various colors are:

• Gallium Arsenide - Phosphide (GaAsP): Used for red, orange, and yellow LEDs.
• Indium Gallium Nitride (InGaN) and Gallium Phosphide (GaP): Typically used for blue, green, and white LEDs.
• Gallium Arsenide - Selenide: This is not typically used for LEDs.
• Scandium Arsenide - Phosphide: This is not a common compound semiconductor used for making LEDs.

The correct compound semiconductor used for making LEDs of different colors is **Gallium Arsenide - Phosphide** (GaAsP), which is widely used for producing red and orange LEDs.

Correct Answer:

Correct Answer: (E) Gallium Arsenide - Phosphide

A diode works under forward bias when a positive voltage is applied to the anode, allowing current to flow through the diode.

• Zener diode operates in reverse bias, where it allows current to flow in reverse direction when a certain breakdown voltage is reached. Therefore, it does not work under forward bias.
• LED (Light Emitting Diode) works under forward bias, and it emits light when current passes through it.
• Photo diode operates in reverse bias, where it generates current in response to light.
• Solar cell works under reverse bias as well.

Thus, the correct answer is LED, which operates under forward bias.

The correct option is (D) : LED

Given:

• NOR gate truth table options (A-E).

Step 1: Recall NOR Gate Logic

A NOR gate outputs 1 only when both inputs are 0. For all other input combinations, the output is 0.

Step 2: Evaluate Each Option

(A) → Correct (NOR output for 0,0).

(B) → Incorrect (should be 1).

(C) → Correct (NOR output for 1,1).

(D) → Correct (NOR output for 1,0).

(E) → Correct (NOR output for 0,1).

Conclusion:

The incorrect configuration is (B).

Given:

• Zener voltage,
• Load current,
• Zener current,
• Unregulated input voltage,

Step 1: Calculate Total Current Through Resistor R

The total current through resistor is the sum of the load current and Zener current:

Step 2: Determine Voltage Drop Across R

The voltage drop across is the difference between the input voltage and the Zener voltage:

Step 3: Compute Resistance R

Using Ohm's Law:

Conclusion:

The value of resistor is 250 Ω.

Answer:

Step 1: Reverse biasing a p-n junction diode involves connecting the p-type material to the negative terminal and the n-type material to the positive terminal of an external voltage source.
Step 2: This external reverse bias increases the width of the depletion zone as it adds to the built-in potential across the junction.
Step 3: The increased depletion zone leads to a higher potential barrier, which impedes the flow of majority carriers across the junction, effectively increasing the resistance of the diode to current flow.
Step 4: Therefore, reverse biasing increases the potential barrier, aligning with option (C).

Step 1: Silicon (Si) and Germanium (Ge) are well-known semiconductors commonly used in electronics.
Step 2: Cadmium Sulfide (CdS) and Gallium Arsenide (GaAs) are compound semiconductors used in various electronic and photonic devices.
Step 3: Antimony (Sb), however, is a metalloid and is typically not classified as a semiconductor; it does not exhibit the semiconductive properties like variable conductivity or bandgap manipulation typical of semiconductor materials.
Step 4: Therefore, Sb is not a semiconductor, correctly aligning with option (B).

The initial kinetic energy of the ball is given by: Substituting kg and m/s: The potential energy at the maximum height is: Given m/s and m: The work done by resistive forces is the difference between the initial kinetic energy and the final potential energy: Approximating, the closest answer is 12.5 J.

Let the mass of the balloon be .
When the balloon is moving upward with an acceleration of , the net force on the balloon is given by Newton’s second law: where: - is the mass of the balloon - is the upward acceleration.
The upward force is: Now, to make the balloon move downward with the same acceleration, we need to add a mass to it, and the net force should be in the downward direction. For the downward motion, the net force is: where is the additional mass to be added. The downward force needed to get the balloon to descend with the same acceleration is equal to the force required to accelerate the added mass: Thus, the mass to be added to the balloon to make it descend with the same acceleration is .