Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
Filter By
Clear Filter

All Questions

 The following reaction occurs in the Blast Furnace where iron ore is reduced to iron metal : Fe2O3(s)+3 CO(g) 2 Fe(l)+3 CO2(g) Using the Le Chatelier’s principle, predict which one of the following will not disturb the equilibrium ?
Option: 1  Removal of CO
Option: 2  Removal of CO2
Option: 3 Addition of CO2
Option: 4 Addition of Fe2O3  
 

\\Fe_{2}O_{3}+3CO \leftrightharpoons 2Fe+3CO \\

According to Le Chatelier's principle change in concentration by changing the amount of reactant or product affect the equilibrium. However, the addition of solid reactant won't affect the concentration.

Therefore, addition of solid Fe2O???3 will not disturb the equilibrium. 

View Full Answer(1)
Posted by

vishal kumar

Magnetic field in a plane electromagnetic wave is given by Expression for corresponding electric field will be : Where c is speed of light.    
Option: 1
Option: 2 
Option: 3
Option: 4 
 

View Full Answer(1)
Posted by

vishal kumar

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads

Two reactions R1 and R2 have identical pre-exponential factors.  Activation energy of R1 exceeds that of R2 by 10 kJ mol−1.  If k1 and k2 are rate constants for reactions R1 and R2 respectively at 300 K, then ln(k2/k1) is equal to : (R=8.314 J mol−1K−1)  
Option: 1 6
Option: 2 4
Option: 3 8
Option: 4 12
 

K=Ae^{\frac{-Ea}{RT}}

\frac{K_{1}}{K_{2}}=e\left ( \frac{Ea_{1}-Ea_{2}}{RT} \right )

Taking log both the sides

ln\left ( \frac{K_{2}}{K_{1}} \right )=\frac{E_{a1}-E_{a2}}{RT}= \frac{10000}{8.314\times 300}=4

View Full Answer(1)
Posted by

vishal kumar

The ore that contains the metal in the form of fluoride is :
Option: 1 Cryolite
Option: 2 Malachite
Option: 3 Magnetite
Option: 4 Sphalerite
 

The formula of the ores -

1) Cryolite-Na_{3}AlF_{6}

[Contains the metal in the form of fluoride]

2) Malachite-\; CuCO_{3}.Cu\left ( OH \right )_{2}

3) Magnetite-Fe_{3}O_{4}

4) Sphalerite-ZnS

 

So, option 1 is correct.

View Full Answer(1)
Posted by

Ritika Jonwal

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Four resistances of 15\Omega ,12\Omega,4\Omega\:\:and\:\:10\Omega respectively in cyclic order to form Wheatstone's network. The resistance that is to be connected in parallel with the resistance of 10\Omega to balance the network is ___________\Omega.
Option: 1 10
Option: 2 5
Option: 3 15
Option: 4 20
 

For balanced Wheatstone bridge \frac{R_1}{R_2}=\frac{R_3}{R_4} \ \ or \ \ \frac{R_1}{R_3}=\frac{R_2}{R_4}

R_2=12 \Omega \ \ and \ \ R_4=4 \Omega

As \frac{R_2}{R_4}=\frac{12}{4}=3

So using R_1=15 \Omega

We get R_3=R_{AD}=5 \Omega 

let we connected x-ohms in parallel to 10-ohm resistance

i.e R_3=5 \Omega=\frac{x*10}{x+10}

we get x=10 \Omega 

 

So the answer will be 10.

View Full Answer(1)
Posted by

vishal kumar

The length of a potentiometer wire is 1200cm and it carries a current of 60mA. For a cell of emf 5V and internal resistance of 20\Omega, the null point on it is found to be at 1000cm. The resistance of whole wire is (in \ \Omega):  
Option: 1 100
Option: 2 80
Option: 3 604
Option: 7 120

 

 

 

   

 

 

In the potentiometer, a battery of known emf  E is connected in the secondary circuit. A constant current I is flowing through AB from the driver circuit. The jockey is a slide on potentiometer wire AB to obtain null deflection in the galvanometer. Let  l be the length at which galvanometer shows null deflection.

Since the potential of wire AB (V) is proportional to the length AB(L). 

 Similarly E \ \ \alpha \ \ \ l

So we get 

\frac{V}{E}=\frac{L}{l}

V=E\frac{L}{l}

V=5\times\frac{1200}{1000}=6V

given current through potentiometer wire =60mA

V=iR

\\60\times10^{-3}R=6\\\Rightarrow R=100\Omega 

So the correct option is 4.

 

View Full Answer(1)
Posted by

vishal kumar

NEET 2024 Most scoring concepts

    Just Study 32% of the NEET syllabus and Score up to 100% marks

A proton with kinetic energy of 1MeV moves from south to north. It gets acceleration of 10^{12}m/s^2 by an applied magnetic field (west to east). The value of magnetic field ( in mT):  (Rest mass of a proton is 1.6\times 10^{-27}kg)
Option: 1 0.71
Option: 2 71
Option: 3 0.071
Option: 4 7.1
 

 

   \begin{array}{l}{\because \mathrm{K.E.}=1.6 \times 10^{-13}=\frac{1}{2} \times 1.6 \times 10^{-27} \mathrm{V}^{2}} \\ \\ {\mathrm{V}=\sqrt{2} \times 10^{7}} \\ \\ {\therefore \mathrm{Bqv}=\mathrm{ma}} \\ \\ {\mathrm{B}=\frac{1.6 \times 10^{-27} \times 10^{12}}{1.6 \times 10^{-19} \times \sqrt{2} \times 10^{7}}} \\ \\ {=0.71 \times 10^{-3} \mathrm{T}} \\ \\ {\text { so } 0.71 \mathrm{mT}}\end{array} 

So option (1) is correct

View Full Answer(1)
Posted by

vishal kumar

The purest form of commercial iron is:
Option: 1 wrought iron
Option: 2 pig iron
Option: 3 scrap iron and pig iron
Option: 4 cast iron
 

The purest form of iron is wrought iron.

Therefore, Option(1) is correct.

View Full Answer(1)
Posted by

Kuldeep Maurya

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads

In a meter bridge experimental S is a standard resistance, R is resistance wire. It is found that balancing length is l=25 cm. If R is replaced by a wire of half length and half diameter that of R of same material, then the balancing distance {l}' (in cm) will now be _____.
Option: 1 40
Option: 2  50
Option: 3 20
Option: 4 30
 

 

 

 

\frac{X}{R}=\frac{75}{25}=3

R=\frac{P^{l}}{A}=\frac{4P^{l}}{\pi d^{2}}

{R}'=\frac{4\rho \left ( \frac{l}{2} \right )}{\pi \left ( \frac{d}{2} \right )^{2}}=2R

then, \frac{x}{{R}'}=\frac{X}{2R}=\frac{3}{2}

l=40.00\; cm

 

View Full Answer(1)
Posted by

avinash.dongre

Among the reactions (a)  - (d), the reaction(s) that does / do not occur in the blast furnace during the extraction of iron is / are :

(a)  CaO+SiO_{2}\rightarrow CaSiO_{3} (b)  3Fe_{2}O_{3}+CO\rightarrow 2Fe_{3}O_{4}+CO_{2} (c)  FeO+SiO_{2}\rightarrow FeSiO_{3} (d)  FeO\rightarrow Fe+\frac{1}{2}O_{2}
Option: 1 (C) and (D)

Option:2  (A)

Option: 3 (A) and (D)

Option: 4 (D)
 

The following reactions do not occur in the blast furnace:

C) \mathrm{FeO}+\mathrm{SiO}_{2} \rightarrow \mathrm{FeSiO}_{3}

D) \mathrm{FeO} \rightarrow \mathrm{Fe}+\frac{1}{2} \mathrm{O}_{2}

 

Therefore, Option(1) is correct.

View Full Answer(1)
Posted by

vishal kumar

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE
filter_img