Introduction to Semiconductors

Q. Does the resistance of semiconductor increase with temperature?

Q.

The electric potential V at a point P(x, y, z) in space is given by V=4x^{​​​​​​​​​​2} volt. Electric field at a point(1m, 0, 2m) in V/m is..

Q. The electric potential at a point (x, y, z) is given by V=-x^2y-xz^3 +4 the electric field E at that point is

Q. If a copper wire is stretched to make its cross sectional radius 0.1% thinner, then what is % increase in its resistence?

Q.

Why is area inversely proportional to resistance?

Q.

How can we calculate potential difference between two points if we if we place cells and resistances between the two points.

Q. how to derive electric potential due to dipole by using cos rule

Q.

14. The temperature co-efficient of resistance of a wire at 0^° C is 0.00125 ^° C-1. At 25^° C its resistance is one ohm. The resistance of the wire will be 1.2 ohm at (1) 225 K (2) 190^° C (3) 260^° C (4) 185 K

Q. Two plates are at potential -10V and 30V. If the separation between them is 2cm. The electric field between them is
1) 2000 V/m
2) 1000 V/m
3) 500 V/m

Q. The resistance of a rectangular block of copper of dimensions 2 mm × 2 mm × 5 m between two square faces is 0.02 Ω. What is the resistivity of copper? (1) 1.6 × 10–8 Ω (2) 1.6 × 10–6 Ω-m (3) 1.6 × 10–8 Ω-m (4) Zero

Q.

Under what condition, the current drawn from the cell is maximum?

Q. Upon a six fold increase in the external resistanceof a circuit, the voltage across the terminalsbattery increases from 5V to 10V. The e.m.f. Ofbattery is

Q. The potential difference across the terminals of a battery is 8.4V when there is a current of 1.5V in the battery from the negative to the positive terminal. When the current is 3.5A in the reverse direction, the potential difference becomes 9.4V. (a) What is the internal resis†an ce of the battery? (b) What is the emf of the battery?

Q. A capacitor acts as an infinite resistance for

(a) DC
(b) AC
(c) DC as well as AC
(d) neither AC nor DC

Q. The following four wires are made of the same material and are at the same temperature. Which one of them has highest electrical resistance?

1. Length $=50\text{cm}$, diameter$=0.5\text{mm}$
2. Length $=100\text{cm}$, diameter$=1\text{mm}$
3. Length$=200\text{cm}$, diameter$=2\text{mm}$
4. Length $=300\text{cm}$, diameter$=3\text{mm}$

Q. Which of the following graphs best represents the variation of resistivity $\left(\rho \right)$ with temperature $\left(T\right)$ for Manganin?

1. 
2. 
3. 
4. 

Q. Which of the following graph represents the variation of resistivity $\left(\rho \right)$ with temperature $\left(T\right)$ for nichrome?

1. 
2. 
3. 
4. 

Q. Read the following statements carefully :
$Y:$ The resistivity of a semiconductor decreases with increases of temperature.
$Z:$ In a conducting solid, the rate of collision between free electrons and ions increases with increase of temperature.
Select the correct statement from the following

1. $Y$ is true but $Z$ is false
2. $Y$ is false but $Z$ is true
3. Both $Y$ and $Z$ are true
4. Both $Y$ and $Z$ are false

Q.

A USB memory stick is an example of which of the following components of computer architecture?

1. Secondary memory

2. Main memory

3. output device

4. CPU

Q. If V be the change in potential between two neighbouring points r apart, then the magnitude of electric field E is given by (1)E = ∆V * ∆r (2)E = ∆V / ∆r (3)E = ∆r / ∆V (4)E = (∆V)^2/ ∆r

Q. A conducting wire has a resistance of $10\Omega$ at $0^{\circ }\text{C}$ and its coefficient of thermal resistance is $\alpha =\frac{1}{273}/{}^{\circ }\text{C}$. The resistance of wire at a temperature ${273}^{\circ }\text{C}$ will be
($\ln e=1$)

1. $20\Omega$
2. $5\Omega$
3. $10e\Omega$
4. $\frac{10}{e}\Omega$

Q.

Is copper a semiconductor?

Q. what is alternating EMF

Q.

A room has AC run for 5 hours a day at a voltage of 220 V. The wiring of the room consists of Cu of 1 mm radius and a length of 10 m. Power consumption per day is 10 commercial units. What fraction of it goes in the joule heating in wires? What would happen if the wiring is made of aluminium of the same dimensions? [ρCu = 1.7 × ${10}^{-8}$ Ω m, ρAl = 2.7 × ${10}^{-8}$ Ω m]

Q. Two resistance coils connected in series have resistance of $600\Omega$ and $300\Omega$ at ${20}^{\circ }C$ and temperature co-efficient of resistances are ${0.001}^{\circ }C$ and ${0.004}^{\circ }C$ respectively. What is the effective temperature coefficient of the combination?

1. $0.001{}^{\circ }{C}^{-1}$
2. $0.002{}^{\circ }{C}^{-1}$
3. $0.003{}^{\circ }{C}^{-1}$
4. $0.004{}^{\circ }{C}^{-1}$

Q.

The temperature coefficient of resistance of a conductor is

1. Positive always

2. Negative always

3. Zero

4. Infinite

Q.

A parallel plate capacitor is to be designed with a voltage rating 1 kV, using a material of dielectric constant 3 and dielectric strength about 10⁷ Vm⁻¹. (Dielectric strength is the maximum electric field a material can tolerate without breakdown, i.e., without starting to conduct electricity through partial ionisation.) For safety, we should like the field never to exceed, say 10% of the dielectric strength. What minimum area of the plates is required to have a capacitance of 50 pF?

Q. Electric potential at any point is V= -5x+3y+√15z , then the magnitude of the electric field is :

Q. How can we say that conductance is reciprocal of resistance??
please explain in simple😊😊..

Q. What is difference between resistance and resistivity