74251. Solutions of the system of equations x+y+z=9,2x+5y+7z=52,2x+y-z=0 is:
74252. If e is the charge of an electron, R is the radius of its orbit and ω is the angular velocity of electron, the magnetic dipole moment μm of the orbit is |μm| = eωR2.
74253. The term independent of x in the expansion of(x2-1/x)9is:
74254. (secA+tanA)(1-sinA)=
74255. Assertion (A): At a temperature of 1000 K, thermionic emission current is about 0.1 A/cm2 of surface.Reason (R): Thermionic emission current is given by Ith = SA0 T2 e-Ew/kT.
74256. At room temperature, the current in intrinsic semiconductor is due to
74257. Which of the following types of bond contains,alternate courses of headers and stretchers as the main feature?
74258. What is meant by batching of concrete?
74259. Ferroelectric materials are those which
74260. Which among the following is not a structural steel section?
74261. Assertion (A): Power loss in a conductor of resistance P = I2R.Reason (R): When a conductor is carrying current with current density J as a result of applied field E, then heat developed/m3/ second = JE.
74262. Assertion (A): For Diamond, μr = 1Reason (R): Diamond is a diamagnetic material.
74263. If n denotes principal quantum number, the angular quantum number l = 0, 1... (n - 1).
74264. Assertion (A): In a perfect capacitor, the current density is given by ω ∈0E0∈'rcos(ωt + 90°), where ∈r' is real part of dielectric constant.Reason (R): In a perfect capacitor, dielectric losses are zero.
74265. Assertion (A): For a solenoid having N turns, .Reason (R): For all magnetic materials, B increases linearly with I.
74266. Assertion (A): From the slope of the line in Figure, we can find permanent dipole moment of the molecules.Reason (R): Total polarization of a polyatomic gas is given by P = N(a e + a i + μ2p / 3kT)E.
74267. Assertion (A): If E is available energy state eV and EF is Fermi level, then probability of energy state E being occupied = 0.5.Reason (R): .
74268. If a piece of wood is placed in a magnetic field
74269. The number of valence electrons in donor impurity are
74270. In a true valence crystal, the bonding between the atoms is accomplished by the sharing of valence electrons.
74271. Which of the following are donor impurities? GoldPhosphorusBoronAntimonyArsenicInduim Select the correct answer using the following codes
74272. In crystalline solids, atoms are stacked in a regular manner.
74273. The temperature below which certain materials are antiferromagnetic and above which they are paramagnetic is called
74274. In metals, the average drift velocity of electron per unit field is called mobility.
74275. In chain surveying at what circumstances ranging is done?
74276. In intrinsic semiconductors, the number of free electrons is equal to the number of mobile holes.
74277. When a material becomes a superconductor, its resistivity becomes
74278. In a piezoelectric crystal, the application of mechanical force will cause
74279. Consider the following statementIf an electric field is applied to an n type semiconductor bar, the electrons and holes move in opposite directions due to their opposite charges. The net currents is both due to electrons and holes with electrons as majority carrierssum of hole and electron currentsdifference between electron and hole currents. Which of above statements are correct?
74280. As the temperature of a pure silicon specimen is increased
74281. Assertion (A): In many materials, dielectric polarization causes mechanical distortion.Reason (R): If dielectric polarization causes mechanical distortion then mechanical distortion must cause dielectric polarization.
74282. Semi conducting materials are all
74283. Silicon and germanium atoms combine orderly into array of atoms located in repetitive geometric pattern. This pattern is called
74284. In a pure sample of silicon
74285. Orbital magnetic dipole moment is due to the motion of electron in its orbit around nucleus.
74286. Assertion (A): ∈r can be determined experimentally by measuring the capacitance of a parallel plate capacitor with and without the dielectric.Reason (R): Capacitance of a parallel plate capacitor = .
74287. In a homogeneous magnetic field H of a solenoid, the core carries a magnetic dipole moment M per unit volume equal to
74288. The field pattern of a solenoid is similar to that of bar magnet.
74289. Assertion (A): In a parallel plate capacitor having area of plate 1 m2 and plate separation 1 m, the capacitance C and resistance R are given by C = ∈0∈'r and R = where ω is frequency, ∈r' and ∈r" are real and imaginary parts of dielectric constant.Reason (R): The imaginary part of electric constant is responsible for dielectric losses.
74290. Assertion (A): Silicon is the most favoured semiconductor material.Reason (R): PIV for silicon diode is more than that for germanium diode.
74291. Assertion (A): When cathode temperature is increased from 2500 K to 2550 K, thermionic emission current may increase by about 50%.Reason (R): Thermionic emission current ∝ T2 e-Ew/kT.
74292. In molecules of ionic crystals, orientation polarization is zero.
74293. Assertion (A): CO2 has no resultant dipole moment but CO has a dipole moment.Reason (R): The structure of CO2 is O = C = O.
74294. For a photoconductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in intensity of optical illumination results in
74295. A permeable substance is one
74296. When subjected to alternating stresses, an insulating material is characterised by complex dielectric constant ∈'r - j∈"r . In such materials, the dielectric losses under alternating stress is proportional
74297. The classes of solid dielectrics are
74298. A 200 turn coil has a self inductance of 10 mH. If the number of turns is doubled, all other quantities remaining the same, the self inductance will be
74299. A material which is lightly repelled by a magnetic field is known as
74300. Which of the following is the poorest conductor of electricity?
Terms And Service:We do not guarantee the accuracy of available data ..We Provide Information On Public Data.. Please consult an expert before using this data for commercial or personal use
Powered By:Omega Web Solutions