Advertisements
Advertisements
A beam of light consisting of two wavelengths 600 nm and 500 nm is used in Young's double slit experiment. The silt separation is 1.0 mm and the screen is kept 0.60 m away from the plane of the slits. Calculate:
- the distance of the second bright fringe from the central maximum for wavelength 500 nm, and
- the least distance from the central maximum where the bright fringes due to both wavelengths coincide.
Concept: undefined >> undefined
The magnitude of the electric field due to a point charge object at a distance of 4.0 m is 9 N/C. From the same charged object the electric field of magnitude, 16 N/C will be at a distance of ______.
Concept: undefined >> undefined
Advertisements
- Assertion (A): Work done in moving a charge around a closed path, in an electric field is always zero.
- Reason (R): Electrostatic force is a conservative force.
Concept: undefined >> undefined
- Assertion (A): In Young's double slit experiment all fringes are of equal width.
- Reason (R): The fringe width depends upon the wavelength of light (λ) used, the distance of the screen from the plane of slits (D) and slits separation (d).
Concept: undefined >> undefined
Answer the following giving reasons:
A p-n junction diode is damaged by a strong current.
Concept: undefined >> undefined
Justify your answers for each case.
State the significance of the negative value of electrostatic potential energy of a system of charges.
Three charges are placed at the corners of an equilateral triangle ABC of side 2.0 m as shown in the figure. Calculate the electric potential energy of the system of three charges.
Concept: undefined >> undefined
A photon of wavelength 663 nm is incident on a metal surface. The work function of the metal is 1.50 eV. The maximum kinetic energy of the emitted photoelectrons is ______.
Concept: undefined >> undefined
In Young's double-slit experiment, the separation between the two slits is d and the distance of the screen from the slits is 1000 d. If the first minima fall at a distance d from the central maximum, obtain the relation between d and λ.
Concept: undefined >> undefined
A semiconductor device is connected in series with a battery, an ammeter and a resistor. A current flows in the circuit. If. the polarity of the battery is reversed, the current in the circuit almost becomes zero. The device is a/an ______.
Concept: undefined >> undefined
In Young's double-slit experiment, the screen is moved away from the plane of the slits. What will be its effect on the following?
- The angular separation of the fringes.
- Fringe-width.
Concept: undefined >> undefined
Draw the circuit arrangement for studying V-I characteristics of a p-n junction diode in (i) forward biasing and (ii) reverse biasing. Draw the typical V-I characteristics of a silicon diode.
Concept: undefined >> undefined
The photon emitted during the de-excitation from the first excited level to the ground state of a hydrogen atom is used to irradiate a photocathode in which the stopping potential is 5 V. Calculate the work function of the cathode used.
Concept: undefined >> undefined
Describe the following term briefly:
minority carrier injection in forward biasing.
Concept: undefined >> undefined
Describe the following term briefly:
breakdown voltage in reverse biasing
Concept: undefined >> undefined
Two horizontal thin long parallel wires, separated by a distance r carry current I each in the opposite directions. The net magnetic field at a point midway between them will be ______.
Concept: undefined >> undefined
In an interference experiment, a third bright fringe is obtained at a point on the screen with a light of 700 nm. What should be the wavelength of the light source in order to obtain the fifth bright fringe at the same point?
Concept: undefined >> undefined
Charges (+q) and (–q) are placed at points A and B respectively which are a distance 2L apart. C is the midpoint between A and B. What is the work done in moving a charge +Q along the semicircle CRD?
Concept: undefined >> undefined
Two circular loops, one of small radius r and the other of larger radius R, such that R >> r, are placed coaxially with centres coinciding. Obtain the mutual inductance of the arrangement.
Concept: undefined >> undefined
Read the following paragraph and answer the questions that follow.
| A semiconductor diode is basically a pn junction with metallic contacts provided at the ends for the application of an external voltage. It is a two-terminal device. When an external voltage is applied across a semiconductor diode such that the p-side is connected to the positive terminal of the battery and the n-side to the negative terminal, it is said to be forward-biased. When an external voltage is applied across the diode such that the n-side is positive and the p-side is negative, it is said to be reverse-biased. An ideal diode is one whose resistance in forward biasing is zero and the resistance is infinite in reverse biasing. When the diode is forward biased, it is found that beyond forward voltage called knee voltage, the conductivity is very high. When the biasing voltage is more than the knee voltage the potential barrier is overcome and the current increases rapidly with an increase in forward voltage. When the diode is reverse biased, the reverse bias voltage produces a very small current of about a few microamperes which almost remains constant with bias. This small current is a reverse saturation current. |
- In the given figure, a diode D is connected to an external resistance R = 100 Ω and an emf of 3.5 V. If the barrier potential developed across the diode is 0.5 V, the current in the circuit will be:
(a) 40 mA
(b) 20 mA
(c) 35 mA
(d) 30 mA - In which of the following figures, the pn diode is reverse biased?
(a)
(b)
(c)
(d)
- Based on the V-I characteristics of the diode, we can classify the diode as:
(a) bilateral device
(b) ohmic device
(c) non-ohmic device
(d) passive element
OR
Two identical PN junctions can be connected in series by three different methods as shown in the figure. If the potential difference in the junctions is the same, then the correct connections will be:
(a) in the circuits (1) and (2)
(b) in the circuits (2) and (3)
(c) in the circuits (1) and (3)
(d) only in the circuit (1) 
The V-I characteristic of a diode is shown in the figure. The ratio of the resistance of the diode at I = 15 mA to the resistance at V = -10 V is
(a) 100
(b) 106
(c) 10
(d) 10-6
Concept: undefined >> undefined
Write the S.I. unit of mutual inductance.
Concept: undefined >> undefined
