Which of the following statements is false ?
Question: Which of the following statements is false ?A rheostat can be used as a potential dividerKirchhoff's second law represents energy conservationWheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.Correct Option: , 4 Solution:...
Read More →A particle is moving in a circular path
Question: A particle is moving in a circular path of radius a under the action of an attractive potential $\mathrm{U}=-\frac{\mathrm{k}}{2 \mathrm{r}^{2}}$. Its total energy is :-$\frac{k}{2 a^{2}}$Zero$-\frac{3}{2} \frac{\mathrm{k}}{\mathrm{a}^{2}}$$-\frac{\mathrm{k}}{4 \mathrm{a}^{2}}$Correct Option: , 2 Solution:...
Read More →Two wires are made of the same material and have the same volume.
Question: Two wires are made of the same material and have the same volume. However wire 1 has crosssectional area $\mathrm{A}$ and wire 2 has cross-sectional area $3 \mathrm{~A}$. If the length of wire 1 increases by $\Delta \mathrm{x}$ on applying force F, how much force is needed to stretch wire 2 by the same amount ?$6 \mathrm{~F}$$9 \mathrm{~F}$$\mathrm{F}$$4 \mathrm{~F}$Correct Option: 1 Solution:...
Read More →Which of the following statements is false ?
Question: Which of the following statements is false ?A rheostat can be used as a potential divider (B)Kirchhoff's second law represents energy conservationWheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.Correct Option: , 4 Solution:...
Read More →An p-n junction D shown in the figure can act as a rectifier.
Question: An p-n junction (D) shown in the figure can act as a rectifier. An alternating current source (V) is connected in the circuit. The current (I) in the resistor R can be shown by: Correct Option: , 3 Solution: When postive cycle enters into diode it is forward bias while for negative half cycle it is reversed bias. So we get only positive cycle in output....
Read More →A time dependent force
Question: A time dependent force $\mathrm{F}=6 \mathrm{t}$ acts on a particle of mass $1 \mathrm{~kg}$. If the particle starts from rest, the work done by the force during the first $1 \mathrm{sec}$. will be :$9 \mathrm{~J}$$18 \mathrm{~J}$$4.5 \mathrm{~J}$$22 \mathrm{~J}$Correct Option: , 3 Solution:...
Read More →A galvanometer having a coil resistance of
Question: A galvanometer having a coil resistance of $100 \Omega$ gives a full scale deflection, when a current of $1 \mathrm{~mA}$ is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of $10 \mathrm{~A}$, is :-$3 \Omega$$0.01 \Omega$$2 \Omega$$0.1 \Omega$Correct Option: , 2 Solution:...
Read More →A body of mass
Question: A body of mass $\mathrm{m}=10^{-2} \mathrm{~kg}$ is moving in a medium and experiences a frictional force $\mathrm{F}=-\mathrm{kv}^{2}$. Its intial speed is $\mathrm{v}_{0}=10 \mathrm{~ms}^{-1}$. If, after $10 \mathrm{~s}$, its energy is $\frac{1}{8} \mathrm{mv}_{0}^{2}$, the value of $\mathrm{k}$ will be :-$10^{-4} \mathrm{~kg} \mathrm{~m} \mathrm{~m}^{-1}$$10^{-1} \mathrm{~kg} \mathrm{~m}^{-1} \mathrm{~s}^{-1}$$10^{-3} \mathrm{~kg} \mathrm{~m}^{-1}$$10^{-3} \mathrm{~kg} \mathrm{~s}^{...
Read More →A point particle of mass,
Question: A point particle of mass, moves along the uniformly rough track PQR as shown in the figure. The coefficient of friction, between the particle and the rough track equals $\mu$. The particle is released, from rest, from the point $\mathrm{P}$ and it comes to rest at a point $\mathrm{R}$. The energies, lost by the ball, over the parts, PQ and PR, of the track, are equal to each other, and no energy is lost when particle changes direction from $\mathrm{PQ}$ to $\mathrm{QR}$. The values of ...
Read More →In the circuit shown, the current in the
Question: In the circuit shown, the current in the $1 \Omega$ resistor is :- $0.13 \mathrm{~A}$, from $\mathrm{Q}$ to $\mathrm{P}$$0.13 \mathrm{~A}$, from $P$ to $Q$$1.3 \mathrm{~A}$, from $\mathrm{P}$ to $\mathrm{Q}$$0 \mathrm{~A}$Correct Option: 1 Solution:...
Read More →When 5 V potential difference is applied across a wire of length 0.1 m,
Question: When $5 \mathrm{~V}$ potential difference is applied across a wire of length $0.1 \mathrm{~m}$, the drift speed of electrons is $2.5 \times 10^{-4} \mathrm{~ms}^{-1}$. If the electron density in the wire is $8 \times 10^{28} \mathrm{~m}^{-3}$, the resistivity of the material is close to :-$1.6 \times 10^{-6} \Omega \mathrm{m}$$1.6 \times 10^{-5} \Omega m$$1.6 \times 10^{-8} \Omega \mathrm{m}$$1.6 \times 10^{-7} \Omega \mathrm{m}$Correct Option: , 2 Solution:...
Read More →A person trying to lose weight
Question: A person trying to lose weight by burning fat lifts a mass of $10 \mathrm{~kg}$ upto a height of $1 \mathrm{~m} 1000$ times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will he use up considering the work done only when the weight is lifted up? Fat supplies $3.8 \times 10^{7} \mathrm{~J}$ of energy per kg which is converted to mechanical energy with a $20 \%$ efficiency rate. Take $\mathrm{g}=9.8 \mathrm{~ms}{ }^{2}$ :-$12.89 \times 10...
Read More →Two moles of an ideal monoatomic gas occupies a volume
Question: Two moles of an ideal monoatomic gas occupies a volume $\mathrm{V}$ at $27^{\circ} \mathrm{C}$. The gas expands adiabatically to a volume $2 \mathrm{~V}$. Calculate (a) the final temperature of the gas and (b) change in its internal energy. (a) $195 \mathrm{~K}$ (b) $-2.7 \mathrm{~kJ}$(b) $189 \mathrm{~K}$ (b) $-2.7 \mathrm{~kJ}$(c) $195 \mathrm{~K}$ (b) $2.7 \mathrm{~kJ}$(d) $189 \mathrm{~K}$ (b) $2.7 \mathrm{~kJ}$Correct Option: , 2 Solution:...
Read More →In a large building, there are 15 bulbs of
Question: In a large building, there are 15 bulbs of $40 \mathrm{~W}, 5$ bulbs of $100 \mathrm{~W}, 5$ fans of $80 \mathrm{~W}$ and 1 heater of $1 \mathrm{~kW}$. The voltage of the electric mains is $220 \mathrm{~V}$. The minimum capacity of the main fuse of the building will be :$12 \mathrm{~A}$$14 \mathrm{~A}$$8 \mathrm{~A}$$10 \mathrm{~A}$Correct Option: 1 Solution:...
Read More →When a rubber-band
Question: When a rubber-band is stretched by a distance $x$, it exerts a restoring force of magnitude $\mathrm{F}=\mathrm{ax}+\mathrm{bx}^{2}$ where $\mathrm{a}$ and $\mathrm{b}$ are constants. The work done in stretching the unstretched rubberband by L is:-$\frac{a L^{2}}{2}+\frac{b L^{3}}{3}$$\frac{1}{2}\left(\frac{\mathrm{aL}^{2}}{2}+\frac{\mathrm{bL}^{3}}{3}\right)$$a L^{2}+b^{3}$$\frac{1}{2}\left(a L^{2}+b L^{3}\right)$Correct Option: 1 Solution:...
Read More →This question has Statement I and Statement II.
Question: This question has Statement I and Statement II. Of the four choice given after the Statements, choose the one that best describes the two Statements. Statement-I : Higher the range, greater is the resistance of ammeter. Statement-II : To increase the range of ammeter, additional shunt needs to be used across it.Statement-I is true, Statement-II is true, Statement-II is the correct explanation of Statement-IStatement-I is true, Statement-II is true, Statement-II is not the correct expla...
Read More →Solve this following
Question: $\mathrm{C}_{\mathrm{p}}$ and $\mathrm{C}_{\mathrm{v}}$ are specific heats at constant pressure and constant volume respectively. It is observed that $C_{p}-C_{v}=a$ for hydrogen gas $C_{p}-C_{v}=b$ for nitrogen gas The correct relation between a and $b$ is : $a=14 b$$a=28 b$$a=\frac{1}{14} b$$a=b$Correct Option: 1 Solution:...
Read More →This question has Statement
Question: This question has Statement-1 and Statement-2. of the four choices given after the statements, choose the one that best describes the two statements. If two springs $\mathrm{S}_{1}$ and $\mathrm{S}_{2}$ of force constants $\mathrm{k}_{1}$ and $\mathrm{k}_{2}$, respectively, are stretched by the same force, it is found that more work is done on spring $S_{1}$ than on spring $S_{2}$. Statement-1: If stretched by the same amount, work done on $\mathrm{S}_{1}$, will be more than that on $\...
Read More →The supply voltage to a room is 120 V .
Question: The supply voltage to a room is $120 \mathrm{~V}$. The resistance of the lead wires is $6 \Omega$. A $60 \mathrm{~W}$ bulb is already switched on. What is the decrease of voltage across the bulb, when a $240 \mathrm{~W}$ heater is switched on in parallel to the bulb?zero Volt$2.9$ Volt$13.3$ Volt$10.04$ VoltCorrect Option: , 4 Solution:...
Read More →At time
Question: At time $\mathrm{t}=0$ s particle starts moving along the $x$-axis. If its kinetic energy increases uniformly with time ' $t$ ', the net force acting on it must be proportional to :-$\sqrt{t}$constant$\mathrm{t}$$\frac{1}{\sqrt{t}}$Correct Option: , 4 Solution:...
Read More →Two electric bulbs marked
Question: Two electric bulbs marked $25 \mathrm{~W}-220 \mathrm{~V}$ and $100 \mathrm{~W}-220 \mathrm{~V}$ are connected in series to a $440 \mathrm{~V}$ supply. Which of the bulbs will fuse ? NeitherBoth$100 \mathrm{~W}$$25 \mathrm{~W}$Correct Option: , 4 Solution:...
Read More →The potential energy function
Question: The potential energy function for the force between two atoms in a diatomic molecule is approximately given by $U(x)=\frac{a}{x^{12}}-\frac{b}{x^{6}}$, where $a$ and $b$ are constant and $x$ is the distance between the atoms. if the dissociation energy of the molecule is $\mathrm{D}=\left[\mathrm{U}(\mathrm{x}=\infty)-\mathrm{U}_{\mathrm{at}}\right.$ equilibrium $]$, $\mathrm{D}$ is :$\frac{b^{2}}{6 a}$$\frac{b^{2}}{2 a}$$\frac{b^{2}}{12 a}$$\frac{b^{2}}{4 a}$Correct Option: , 4 Soluti...
Read More →A telephonic communication service is working at carrier frequency of
Question: A telephonic communication service is working at carrier frequency of $10 \mathrm{GHz}$. Only $10 \%$ of it is utilized for transmission. How many telephonic channels can be transmitted simultaneously if each channel requires a bandwidth of $5 \mathrm{kHz}$ ?$2 \times 10^{4}$$2 \times 10^{5}$$2 \times 10^{6}$$2 \times 10^{3}$Correct Option: , 2 Solution: Since the carrier frequency is distributed as band width frequency, so $10 \%$ of $10 \mathrm{GHz}=\mathrm{n} \times 5 \mathrm{kHz}$ ...
Read More →A telephonic communication service is working at carrier frequency of
Question: A telephonic communication service is working at carrier frequency of $10 \mathrm{GHz}$. Only $10 \%$ of it is utilized for transmission. How many telephonic channels can be transmitted simultaneously if each channel requires a bandwidth of $5 \mathrm{kHz}$ ?$2 \times 10^{4}$$2 \times 10^{5}$$2 \times 10^{6}$$2 \times 10^{3}$Correct Option: Solution: Since the carrier frequency is distributed as band width frequency, so $10 \%$ of $10 \mathrm{GHz}=\mathrm{n} \times 5 \mathrm{kHz}$ wher...
Read More →In amplitude modulation, sinusoidal carrier frequency used is denoted by
Question: In amplitude modulation, sinusoidal carrier frequency used is denoted by $\omega_{\mathrm{c}}$ and the signal frequency is denoted by $\omega_{\mathrm{m}^{*}}$. The bandwidth $\left(\Delta \omega_{\mathrm{m}}\right)$ of the signal is such that $\Delta \omega_{\mathrm{m}} \ll \omega_{\mathrm{c}}$. Which of the following frequencies is not contained in the modulated wave ?$\omega_{\mathrm{m}}+\omega_{\mathrm{c}}$$\omega_{c}-\omega_{m}$$\omega_{\mathrm{m}}$$\omega_{c}$Correct Option: , 3 ...
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