Unbalanced reaction to balance with answers key

 Q balance the following reactions 

1. NaH2PO4 -> NaPO3 + H2O
2. H2CO3 -> H2O + CO2
3. BaSO4 + H2SO4 -> Ba(HSO4)2
4. CaCO3 -> CaO + CO2
5. CaO + H2O -> Ca(OH)2
6. H2SO3 -> H2O + SO2
7. H3PO4 + Ca(OH)2 -> CaHPO4.2H2O
8. NaPO3 + CuO -> NaCuPO4
9. SO3 + H2O -> H2SO4
10. Be(OH)2 -> BeO + H2O
11. BaO + H2O -> Ba(OH)2
12. Na2SO3 + S -> Na2S2O3
13. SO2 + H2O -> H2SO3
14. Li2O + H2O -> LiOH
15. Na2HPO4 -> Na4P2O7 + H2O
16. H4As2O7 -> As2O5 + H2O
17. CaC2 + N2 -> CaCN2 + C
18. Mg(OH)2 -> (MgOH)2O + H2O
19. HAsO3 -> As2O5 + H2O
20. KHSO4 -> K2S2O7 + H2O
21. H3PO4 -> H4P2O7 + H2O
22. NaCl + NH4HCO3 -> NaHCO3 + NH4Cl
23. HAsO2 -> As2O3 + H2O
24. UO3 + H2 -> UO2 + H2O
25. CdSO4 + H2S -> CdS + H2SO4

Answers Key

1. Balanced
2. Balanced
3. Balanced
4. Balanced
5. Balanced
6. Balanced
7. Balanced
8. Balanced
9. Balanced
10. Balanced
11. Balanced
12. Balanced
13. Balanced
14. Li2O + H2O -> 2LiOH
15. 2Na2HPO4 -> Na4P2O7 + H2O
16. H4As2O7 -> As2O5 + 2 H2O
17. CaC2 + N2 -> CaCN2 + 2C
18. 2Mg(OH)2 -> (MgOH)2O + H2O
19. 2HAsO3 -> As2O5 + H2O
20. 2KHSO4 -> K2S2O7 + H2O
21. 2H3PO4 -> H4P2O7 + H2O
22. Balanced
23. 2HAsO2 -> As2O3 + H2O
24. Balanced
25. Balanced

MCQs on Complex no, class 11th

Instructions

• Each question carry 2 Marks
• Total 40 marks test, 20 questions
• Time- 90 minutes
• Answer key will be provided after the exam get over

Q1) The value of √(-121)  is

(a) -11i

(b) 11i

(c) -12i

(d) 12i

Q2)  The value of √(-441) is

(a) 21i

(b) -21i

(c) ±21i

(d) All of these

Q3) The value of √(-25) + 3√(-4) + 2√(-9) is

(a) 13i

(b) -13i

(c) 17i

(d) -17i

Q4)  If z lies on |z| = 1, then 2/z lies on

(a) a circle

(b) an ellipse

(c) a straight line

(d) a parabola

Q5)  If ω is an imaginary cube root of unity, then (1 + ω – ω²)7 equals

(a) 128 ω

(b) -128 ω

(c) 128 ω²

(d) -128 ω²

Q6)  The least value of n for which {(1 + i)/(1 – i)}n is real, is

(a) 1

(b) 2

(c) 3

(d) 4

Q7)  Let z be a complex number such that |z| = 4 and arg(z) = 5π/6, then z =

(a) -2√3 + 2i

(b) 2√3 + 2i

(c) 2√3 – 2i

(d) -√3 + i

Q8)  The value of i-999 is

(a) 1

(b) -1

(c) i

(d) -i

Q9)  Let z1 and z2 be two roots of the equation z² + az + b = 0, z being complex. Further assume that the origin, z1 and z1 form an equilateral triangle. Then

(a) a² = b

(b) a² = 2b

(c) a² = 3b

(d) a² = 4b

Q10)  The complex numbers sin x + i cos 2x are conjugate to each other for

(a) x = nπ

(b) x = 0

(c) x = (n + 1/2) π

(d) no value of x

Q11) The curve represented by Im(z²) = k, where k is a non-zero real number, is

(a) a pair of striaght line

(b) an ellipse

(c) a parabola

(d) a hyperbola

Q12)  The value of x and y if (3y – 2) + i(7 – 2x) = 0

(a) x = 7/2, y = 2/3

(b) x = 2/7, y = 2/3

(c) x = 7/2, y = 3/2

(d) x = 2/7, y = 3/2

Q13) Find real θ such that (3 + 2i × sin θ)/(1 – 2i × sin θ) is imaginary

(a) θ = nπ ± π/2 where n is an integer

(b) θ = nπ ± π/3 where n is an integer

(c) θ = nπ ± π/4 where n is an integer

(d) None of these

Q14) If {(1 + i)/(1 – i)}n = 1 then the least value of n is

(a) 1

(b) 2

(c) 3

(d) 4

Q15) If arg (z) < 0, then arg (-z) – arg (z) =

(a) π

(b) -π

(c) -π/2

(d) π/2

Q16) if x + 1/x = 1 find the value of x2000 + 1/x2000 is

(a) 0

(b) 1

(c) -1

(d) None of these

Q17) The value of √(-169) is

(a) 13i

(b) -13i

(c) ±13i

(d) None of these

Q18) If the cube roots of unity are 1, ω, ω², then the roots of the equation (x – 1)³ + 8 = 0 are

(a) -1, -1 + 2ω, – 1 – 2ω²

(b) – 1, -1, – 1

(c) – 1, 1 – 2ω, 1 – 2ω²

(d) – 1, 1 + 2ω, 1 + 2ω²

Q19)  (1 – w + w²)×(1 – w² + w4)×(1 – w4 + w8) × …………… to 2n factors is equal to

(a) 2n

(b) 22n

(c) 23n

(d) 24n

Q20) The modulus of 5 + 4i is

(a) 41

(b) -41

(c) √41

(d) -√41

Class 11th: Chapter 1 : Physics

 Units and Measurements

Q1.  Choose the correct option. (4M)

 i) The error in the measurement of the 

sides of a rectangle is 1%. The error in 

the measurement of its area is

 (A) 1% (B) 1/2% 

 (C) 2% (D) None of the above.

 ii) Light year is a unit of 

 (A) Time (B) Mass

 (C) Distance (D) Luminosity

 iii) Dimensions of kinetic energy are the 

same as that of 

 (A) Force (B) Acceleration

(C) Work (D) Pressure

 iv) Which of the following is not a 

fundamental unit?

 (A) cm (B) kg 

 (C) centigrade (D) volt

Q2 The radius of a sphere measured repeatedly yields values 5.63 m, 5.54m, 5.44 m, 5.40 m and 5.35 m. Determine the most probable value of radius and the mean absolute, relative and percentage errors.             (3M)

Q3 The masses of two bodies are measured to be 15.7 + 0.2 kg and 27.3 + 0.3 kg.  What is the total mass of the two and the error in it?                      (3M)

P-block elements:imp questions : class12th

 p-block elements (15Marks)

Q1.Discuss the general characteristics of Group 15 elements with reference to their electronic configuration, oxidation state, atomic size, ionisation enthalpy

and electronegativity. (5M)

Q2. Why does NH3 form hydrogen bond but PH3 does not?                                   (1M)

Q3. Give the resonating structures of NO2 and N2O5.

                                            (2M)

Q4. How is ammonia manufactured industrially?

Explain with experimental diagram.                           (3M)

Q5. Why does the reactivity of nitrogen differ from phosphorus?                   (2M)

Q6. Why does nitrogen show catenation properties less than phosphorus?          (2M)

Deleted portion of Physics due to Covid 19 Pendamic : Class 11th : 2020-21

Deleted portion of Class 11th Physics due to Covid 19 Pendamic (2020-21)

Chapter 1 Units and Measurements 

1) 3 to 5 1.3 Measurement of length                

2) 5 1.4 Measurement of Mass.                          

3 ) 5 to 6 1.5 Measurement of Time                  

4) 8 1.7 Accuracy,Precision and Uncrtainity in measurement                                                  

5) 10 to 11 1.8.2 Combination of errors

Chapter 2 Mathematical Methods

1) 25 - 28 2.6 Introduction to Calculus

Chapter 3 Motion in a Plane

1) 30 - 36 3.2 Rectilinear Motion

Chapter 4: Laws of motion

1) 47 4.2 Aristotle’s fallacy                                

2) 48 4.3 only Newton’s laws of motion          

4) 52 4.5.2 Contact and non-contact forces    

6) 55, 56 4.6 Work energy theorem                  

7) 56, 57 4.7 Principle of conservation of linear momentum                                                

8 ) 61 4.8.5 Loss in K.E….Use the result 4.11 without proof                                                    

10) 63 to 64 4.9.1 Necessity of defining impulse                                                               

11) 67 4.11.1 To prove that the moment of a couple is independent of the axis of rotation 

12) 72 4.13.4 characteristics of Centre of mass 

Chapter 5 Gravitation

1) 84 5.4 Measurement of the Gravitational Constants

Chapter 6 Mechanical Properties of solid

1) 108 6.8 Hardness   

2) 109 - 111 6.9 Friction in Solid

Chapter 7 Thermal Properties of Matter

1) 114 7.2 Temperature and Heat

2) 115 -118 7.3 Measurement of Temperature

3) 118 -121 7.4 Absolute Temperature and Ideal Gas Equation

4) 129 -133 7.8 Change of State

Chapter 8: Sound Waves

2) 142 -144 8.2 Common Properties of all Waves

3) 144 -145 8.3 Transverse Waves, Longitudinal Waves 

4) 149 8.6 Principle of Superposition of Waves

5) 150 8.7.2 Reverberation

6) 150 to 151 8.7.3 Acoustics

7) 154 8.9.2 Listener Approaching a Stationary Source with velocity v

Chapter 9: Optics 

1) 159 9.2 Nature of light

2) 159 - 161 9.3 Ray optics and geometrical optics

4) 162 9.4.2 Relation between f , u and v

5) 166, 167 9.6.1 (ii, iii) Prism binoculars and periscope

6) 167 9.7 Till equation 9.2

11) 175 to 177 9.9 Natural phenomena due to sunlight

12) 183 - 184 9.11 (last part) Telescope onwards, till the end.

Chapter 10 Electrostatics

1) 188 10.2 Electric charge

2) 195 10.6.1 Electric field intensity due to point charge in a material medium

3) 196 10.6.2 Practical way of calculating electric field

4) 199 10.8 Proof of the Gauss’ law

5) 201 -204 10.9 Electric dipole

8) 204 10.10 Continuous charge distribution

Chapter 11 Electric Current Through Conductors

1) 207 11.2 Electric current

2) 207 11.3 Flow of current through a conductor

3) 207-208 11.4 Drift speed

4) 209 11.5 Ohm's law

5) 210 11.6 Limitations of the Ohm's law

6) 210 11.7 Electrical energy and power

7) 211-213 11.8 Resistors

8) 213 11.9 Specific Resistance(Resistivity)

Chapter12 Magnetism

1) 224-225 12.4 Gauss' Law of Magnetism

Chapter13: Electromagnetic Waves and Communication System 

3) 234-235 13.3.5-13.3.7 UV , X & Gamma Rays

5) 239 13.6 Modulation

Chapter 14 Semiconductors

1) 254 14.8 Semiconductor devices.

Units and Measurements:Class 11th

 

Current Electricity 11th

Resistance. The electrical resistance of a circuit  device is defined as the ratio of the voltage applied to the electric current which flows through it: If the resistance is constant over a considerable range of voltage, then Ohm's law, 

                                       I = V/R, 

can be used to predict the behavior of the material.

Resistivity, commonly symbolized by the Greek letter rho, ρ, is quantitatively equal to the resistance R of a specimen such as a wire, multiplied by its cross-sectional area a, and divided by its length l; ρ = Ra/l.

Ohm's law in terms of Resistance R= V/I

Resistances in Series : 
                      

         V =V1 + V2 + V3

            IR = IR1 + IR2 +IR3

                  = I(R1 + R2 +R3)

             R  =   R1 + R2 + R3

Resistances in Parallel : 

         I = I1 + I2 

       V/Rp = V/R1 + V/R2

           V/Rp = V(1/R1 + 1/R2)

       1/Rp = 1/R1 + 1/R2

                   Rp = R1R2 / (R1 + R2)

Deleted portion of Physics:class 12th : 2020-21

^{70 Marks(Theory)+30 Marks(Practical)}

Class 12th : Portion Deleted for year 2020-21 of Physics.

Chapter 1 Rotational Dynamics
1) 11 1.4.2 Sphere of Death
2) 11 1.4.3 Vehicle at the Top of a Convex Over Bridge
3) 19-20 1.11 Rolling Motion
Chapter 2 Mechanical Properties Of Fluids
1) 27-33 2.3 Pressure
2) 48-49 2.8 Equation of Continuity
3) 50-53 2.9 Bernoulli Equation
Chapter 3 Kinetic Theory Of Gases and Radiation
1) 56 3.2 Behaviour of a gas
2) 57 3.3 Ideal Gas and Real Gas
3) 57 3.4 Mean Free Path
4) 61-62 3.8 Law of Equipartition of Energy
Chapter 4 Thermodynamics
1) 96 4.8 Heat Engines
2) 99 4.9 Refrigerators and Heat Pumps
3) 102 4.10 Second Law of Thermodynamics
4) 104 4.11 Carnot Cycle and Carnot Engine
5) 106 4.12 Sterling Cycle
Chapter 5 : Oscillations
1) 116-117 5.7 Reference Circle Method
2) 118-119 5.9 Graphical representation of S.H.M.
3) 126-127 5.14 Damped Oscillations
4) 127-128 5.15 Free Oscillations,Forced Oscillations and Resonance
Chapter 6: Superposition of Waves
1) 132-133 6.3 Reflection of waves
2) 153 6.1O Characteristics of sound
3) 154 6.11 Muscical Instruments
Chapter 7 : Wave Optics
1) 158 7.2. Corpuscular Nature
2) 164 7.6 Refraction of a light at a Plane Boundary between two media
3) 164 7.7 Polarization
4) 180 7.1O Resolving power
Chapter 8 : Electrostatics
1) 194-195 8.5 Equipotential Surfaces
2) 199 8.7 Conductors and insulators, Free charges and Bound charges
3) 208 8.11 Displacement current
4) 210-211 8.13 Van de Graaff Generator
Chapter 10 Magnetic Fields due to Electric Current
1) 232-234 10.3 Cyclotron Motion
2) 234 10.4 Helical Motion
Chapter 11 Magnetic Materials
1) 251-253 11.2 Torque Acting on a Magnetic Dipole in a Uniform Magnetic Field
2) 257-261 11.5 Magnetic Properties of Materials
3) 261-262 11.6 Hysteresis
4) 262 11.7 Permanent Magnet and Electromagnet
5) 262 11.8 Magnetic Shielding
Chapter 12 Electromagnetic Induction
1) 270-273 12.6 Induced emf in a Stationary Coil in a Changing Magnetic Field
2) 273-274 12.7 Generator
3) 274-276 12.8 Back emf and back torque
4) 281 12.13 Energy Density of a Magnetic Field
Chapter 13 AC Circuits
1) 288 13.2 A.C. Generator
2) 297-299 13.6 Power in A.C. Circuits
3) 302-303 13.9 Sharpness of Resonance: Q factor
4) 303 13.10 Choke coil
Chapter 14 Dual Nature of Radiation and Matter
1) 314 Table 14.2 Summary of analysis of observations from
2) 316 14.4 Photo Cell
3) 318-319 14.6 Davison and Germer Experiment
Chapter 15 Structure of Atoms and Nuclei
1) 324 15.3 Geiger Marsden Experiment
2) 330-332 15.7 Atomic Nuclues
3) 332-333 15.8 Nuclear Binding Enenergy
4) 333-336 15.9 Radioactive Decays
5) 338-341 15.11 Nuclear energy
Chapter 16 Semiconductor Devices
1) 347-350 16.3.1 Zener Diode

Chapter 01 : Maths: XI : Trigonometry : Identities

Basic Identities

Here we have divided Pythagorean triplet by C^2

Current Electricity Question Paper CLASS 12TH

PATHAK’S ACADEMY SPECTRUM

TOPIC : Current Electricity         CLASS : 12^th    BOARD : STATE/CBSE

==========================================

Q1) State and explain Kirchhoff’s Voltage law.(2)

Q2) State any two advantages of Potentiometer over Voltmeter.(2)

Q3) A Voltmeter has resistance of 100 Ω.  What it will show when connected across the cell of emf 2V and internal resistance 20Ω ?(2)

Q4) Explain the principal of potentiometer with neat lablled diagram.(3)

Q5) Obtain the balancing condition for Wheatstone’s bridge Network with suitable diagram.(3)

Q6) A Cell with internal Resistance 2.5 Ω is balanced across 450 cm length of Potentiometer wire. The cell is shunted by a resistance of 4 Ω . Calculate the balancing length.(3)

Q7) Explain the use of potentiometer to compare the emfs of two cells bu sum and difference method. A Potentiometer wire has length of 2m and resistance 10 Ω  . It is connected in series with resistance 990Ω and a cell of emf 2V. Calculate the potential gradient along the wire. (4)

Q8) Explain with neat lablled diagram, how will you determine the unknown resistance by using Meter Bridge Experiment. The current flowing through the external resistance of 2Ω. is 0.5 A when it is connected to the terminal of a cell. The current reduces to 0.25 A when external resistance is 5Ω. Use Kirchoff law to find emf of cell. (4)

Q9) Four resistances 4Ω , 8Ω, XΩ ,6Ω  are connected in series so as to form Wheatston’s bridge Network. If the Network is balanced find the value of X. (2)