Recent questions in Physics

The population in a particular area is 1000 per square kilometer.What should be the height of the transmission tower to cover a population of 10 lakhs. For the sake of simplicity, assume that the Radius of earth is 6,400 Km.

asked Mar 17, 2014 by sreemathi.v

1 answer

What is the length of half wave dipole antenna at 100MHz

asked Mar 17, 2014 by sreemathi.v

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The range of frequency used in television broadcasting is

asked Mar 17, 2014 by sreemathi.v

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Critical frequency $\nu_c$ for ionsphere is

asked Mar 17, 2014 by sreemathi.v

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The basic radio antenna is a metal rod,the length of which is

asked Mar 17, 2014 by sreemathi.v

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Bandwidth is dependent on

asked Mar 17, 2014 by sreemathi.v

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For commercial FM-transmission maximum frequency deviation allowed is

asked Mar 17, 2014 by sreemathi.v

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In frequency modulation (FM) the

asked Mar 17, 2014 by sreemathi.v

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In which of the following remote sensing technique is not used

asked Mar 17, 2014 by sreemathi.v

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An oscillator is producing FM waves of frequency 3KHz with a variation of 9KHz what is the modulating index

asked Mar 17, 2014 by sreemathi.v

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A carrier wave is modulated to 75%.If the power of carrier wave is 500W what is power of modulated wave

asked Mar 17, 2014 by sreemathi.v

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An audio frequency of $4\times 10^3$ Hz is used to modulate a carrier wave of frequency 1MHz.The band width is

asked Mar 17, 2014 by sreemathi.v

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A amplitude modulated wave has maximum amplitude of 700mV and minimum amplitude of 200mV.Calculate the modulation factor

asked Mar 17, 2014 by sreemathi.v

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A TV tower has a height of 100m.If the coverage range is to be made three times then by how much should the height of the tower be increased.

asked Mar 17, 2014 by sreemathi.v

1 answer

Calculate the standard entropy change for a reaction $XY$ if the value of $\Delta H^{\circ} = 28.4 \: kJ$ and equilibrium constant is $1.8 \times 10^{-7}\: at\: 298\: K$ .

asked Mar 16, 2014 by thanvigandhi_1

1 answer

Calculate the standard free energy change for the following reaction $Zn(s) + Cu^{2+} (aq) \rightarrow Cu(s) + Zn^{2+} (aq)$ Given that $\Delta G_f^{\circ}\: for \: Cu^{2+} (aq)\: and \: Zn^{2+} (aq)$ as 65 kJ/mol and -147.2 kJ/mol respectively.

asked Mar 16, 2014 by thanvigandhi_1

1 answer

For the reaction $N_2(g) + 3H_2(g)\rightarrow 2NH_3(g) \Delta H = -95.4 \: kJ\: and\: \Delta S = -198.3\: J/K$ Calculate the temperature at which free energy change is equal to zero.

asked Mar 16, 2014 by thanvigandhi_1

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Calculate the entropy change when 36 g of liquid water evaporates at $373\: K( \Delta H_{vap} = 40.63\: kJ/mol)$

asked Mar 16, 2014 by thanvigandhi_1

1 answer

Calculate the entropy change for the conversion of 1 gm of ice to water at 273 K and one atm pressure. The enthalpy of fusion of ice is 6.025 kJ/mol

asked Mar 16, 2014 by thanvigandhi_1

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Calculate the bond energy of $Cl-Cl$ bond from the following data: $CH_4(g) + Cl_2(g) \rightarrow CH_3Cl(g) + HCl(g); \Delta H = -100.3\: kJ$ . Also the bond energies of $C-H,\: C-Cl,\: H-Cl$ bonds are 413, 326 and 431 kJ/mol respectively.

asked Mar 16, 2014 by thanvigandhi_1

1 answer

Calculate the enthalpy change ( $\Delta H$ ) of the following reaction: $2C_2H_2(g) + 5O_2(g) \rightarrow 4CO_2(g) + 2H_2O(g)$ given average bond energies of various bonds, i.e, $C-H,\: CC,\: O=O,\: C=O,\: O-H$ as 414, 814, 499, 724 and 640 kJ/mol respectively.

asked Mar 16, 2014 by thanvigandhi_1

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Calculate standard internal energy change( $\Delta E^{\circ}$ ) for the reaction $OF2(g) + H_2O(g) \rightarrow O_2(g) + 2HF(g)$ Given standard enthalpies of formation $\Delta H_f^{\circ}\: of\: OF_2(g), H_2O(g)\: and\: HF(g)$ are23, -241.8 and -268.6 kJ/mol respectively.

asked Mar 16, 2014 by thanvigandhi_1

1 answer

2.5 mol of ideal gas at 2 atm and $27^{\circ}C$ expands isothermally to 2.5 times of its original volume against the external pressure of 1 atm. Calculate q

asked Mar 16, 2014 by thanvigandhi_1

1 answer