PHYSICS, GROUP FIRST       
TIME: 20 MINUTES
MARKS: 17
OBJECTIVE

NOTE: You have four choices for each objective type question as A, B, C and D The choices which You think (is correct, fill hat circle in front or that question number. Use marker or per to fill the circles, Cutting or filling two or more: circles will result in zero mark in that question, Attempt as many questions as given in objector type question paper and leave others blank, Write the letter. A B C or D in the column (Write correct option) against each question If the is contradiction in the bubble and hand write answer bubble option will be considered correct

QUESTION No. 1

• A positively charge particle of certain mass may be held suspended (at rest) in electric field of suitable Strength if the field is directed.
  

(a) out ward          
(b) in word                  
(c) up word                 
(d) down word

• when an RC circuit is connected across battery amount of charge deposited on plates is times the equilibrium charge after one time constant.
  

(a) 0.63                             
(b) 0.67                                   
(c) 0.75                                   
(d) 0.86

• If a resistor of resistance R is connected across a battery of internal resistance ‘r’ then output power Will be maximum when
  (a) R =            
  (b) R = r          
  (c) R = 2r                    
  (d) R = 4r
  
• In the colour code of resistance orange colour represents
  

(a) 0        
(b) 1    
(c) 2                
(d) 3

• The unit of permeability (Ho) of free space is
  

(a)                  
(b)                        
(c)              
(d)

• The relation is know as
  

(a) Ampere’s Law           
(b) Faraday’s Law
(c) Lenz’s Law      
(d) Kirchhoff’s Law

• Ina transformer which of the following quantities has same value in primary and secondary
  

(a) Rate of changes of magnetic flux      
(b) Voltage          
(c) Current                  
(d) None of them

• The reactance X c of a capacitor when connected across an AC source of frequency ‘f ’ is given by
  

(a) 2π fC             
(b)                        
(c)              
(d)

• During frequency modulation when amplitude of signal is zero the frequency of carrier waves is
  

(a) Zero   
(b) Maximum  
(c) Minimum               
(d) Normal

• Out of the following which material is brittle
  

(a) High carbon steel       
(b) Aluminium    
(c) Copper
(d) Tungsten

• The coercive current is
  

(a) Magnetizing current   
(b) Current due to holes  
(c) Demagnetizing current
(d) Current due to ions

• Which one of the following is not a basic logic gate
  

(a) NOT gate       
(b) NOR gate  
(c) AND gate              
(d) OR gate

• In the relation λm XT = constant the constant is known as
  

(a) Stefan-Boltzman constant
(b) Plank’s constant          
(c) Compton wavelength   
(d) Wien’s constant

• According to uncertainly principle the quantities which can not be simultaneously measured with Accuracy, are
  

(a) Energy and momentum         
(b) Position and momentum
(c) Position and energy
(d) Momentum and time

• The radiation used to diagnose of eye is
  

(a) Ultra-violet rays    
(b) X-rays
(c) He-Ne laser           
(d) Radio waves

• 14 = …………… Mev
  

(a) 1.6606 x 10^-27
(b) 211.5         
(c) 931            
(d) 0.51

• Dr. Abdus Salam was awarded noble Prize for unification of
  

(a) gravitational force and weak nuclear force    
(b) Strong nuclear force and weak nuclear force
(c) Electromagnetic force and Strong nuclear force
(d) Electromagnetic force and weak nuclear force

SUBJECTIVE 
MARKS 65
SECTION.I

QUESTION NO. 2 Write short answers any Eight (8) questions of the following (16)     

• How can you identify that which plate of a capacitor is positively' charged
• Electric lines of force never cross. Why "
• Show that 1 NC^-1  = 1 Vn^-1
• Define Ohmic and non-Ohmic devices
• Is the filament resistance lower or higher in a 500 W, 220 V high' bath than in a 100 W 220 bulb
• How is the drift speed of free electrons in a copper wire affected by
  (a) Decreasing the length r and (b) decreasing the temperature of the wire?
• What should be the orientation of a current carrying coil in a magnetic field so that the torque acting upon the coil is
  (a) maximum . (b) minimum ?
• Why the resistance of an ammeter should be very low?
• Define Lorentz force
• Does the induced emf in r circuit depend on its resistance? Does the induced current depend  on the resistance of the circuit?
• How will you position a t at loop of wire in a changing magnetic filed so that there is no emf induced in the loop
• Four unmarked wire emerge from a transformer. What steps would you take to determine the turn ratio

QUESTION NO. 3 Write short answers any Eight (8) questions of the following: (16)     

• A metal rod of length 0.25 m is moving at a speed of 0.5 m/sec in a direction perpendicular to a 0.25 T magnetic field. Find the emf produced in the rod
• What is meant by AM and F.M
• How the reception of a particular radio station is selected on your radio selected on your radio set
• Does Doubling the frequency affect the reactance of (a) an inductor (b) a capacitor Explain
• Define stress and strain. What are their SI units?
• What is meant by paramagnetic and diamagnetic substances ? Give example for each
• How the conductivity of conductor can be raised ?
• What is the affect of forward and reverse baiting of a diode on the width of depletion region ?
• The inputs of a gate are' I' and '0' . Identify the gate if its out put is (a) ' 0 ' (b) ' I'
• Draw circuit diagram used for full wave rectification. Show direction of current in the circuit  when positive half of input A.C cycle passes through it
• We do not notice the de-Broglie wavelength for a pitched cricket hall. Explain Why?
• Can pair production take place in vaccum? Explain

QUESTION N0.4 Write short answers any Sit 01 questions of the following                      12

• Is it possible to create a s ngle electron from energy ? Explain
• Describe some uses of photo cell
• Explain why laser action could not occur with out population inversion between atomic levels
• What do we mean when we say that atom is excited
• What are the advantages of lasers over ordinary light?
• What factors make a fusion reaction difficult to achieve?
• What do we mean the tern critical mass and critical volume?
• Nuclear energy released under fusion reaction is greater than the energy released fission reaction.Although release of energy per fission is 200 Mev as compared to 25 Mev per fusion. Comment
• Why are heavy nuclei unstable ?

SECTION-II

Note: Attempt any THREE questions from this section        8 X 3 = 24

5. (a)  Define capacitance and its units. also derive expression for capacitance of a parallel plate Capacitor when there is vacuum between in plates
(b)  The potential difference between the terminals of a battery in open circuit is 2.2 V. When it is Connected a across a resistance of 5.0 the potential falls to 1.8 V . Calculate the internal
resistance of battery   

6. (a) State Ampere's Law and apply it to find the magnetic induction due to current in a solenoid
(b)     A DC motor operates at 240 V and has a resistance of 0.5 When the motor is running at speed the armature current is 15 A . Find the back emf in the armature

7 (a)  Explain RLC- Series circuit?
(b) A 1.25 Cm diameter cylinder is subjected to a load of 2500 K.g Calculate the stress on the bar in Mega pasclas?  

8(a) What are logic gates? Describe fundamental logic gates in detail
(b)    What is the De-Broglie wavelength  of an electron whose K.E is 120 e.v?

9.  (a)  Evaluate the relation for nth orbit of H-atom and justify that radil are quantized
(b) How much energy is observed by a man of mass 80 kg who recives a lethal whole body Equivalent dose of 400 rem in the from of low energy neutrins for which RBE factor is 10            

PAPER CODE - 4472
(12th CLASS - 12012)
PHYSICS , GROUP SECOND
TIME: 20 MINUTES MARKS: 17
OBJECTIVE

NOTE: You have four choices for each objective type question as A , B , C and D . The choice which  you think is correct , fill that circle in front of that question number. Use marker or pen to fill the circles. Cueing or filling two or more circles will result in zero mark in that question. Attempt  as many questions as given in objective type question paper and leave others blank. Write the letter  A , B , C or Din the column (Write correct option) against each question. If there is a contradiction  in the bubble and hand written answer , bubble option will be considered correct

QUESTION NO. I

• Two equal and opposite point charges separated by a distance 2d . The electric potential at the midway between them is
  

(A) Zero     
(B) High
(C) Low     
(D) Constant

• Energy density in case of a capacitor is always proponional to
  

(A) Ԑ°        
(B) C
(C) V2        
(D) E2        

• The couple C for unit twist of the suspension wire can be decreased by

(A) increasing its length
(B) decreasing its length
(C) increasing its diameter
(D) it cannot be decreased

• Direction of torque on a current carrying coil is
  

(A) Clockwise
(B) Anticlockwise
(C) regular reversal of clockwise and anticlockwise
(D) No direction

• SI unit of mutual inductance is
  

(A) AS V^-1   
(B) AS¹V    
(C) AV^-1 S^-1
(D) VS A^-1

• When current flows through the armature coil then the torque produced depends upon
  

(A) rotation of the coil
(B) area of the coil
(C) mutual induction
(D) all of the above 

• Reactance of inductor is very high when there is
  

(A) high frequency current
(B) low frequency current
(C) high frequency inductor
(D) low frequency inductor

• Metal detector works with the help of
  

(A) RC circuit
(3) RI circuit
(C) LC circuit
(D) RLC series circuit

• Strain energy in deformed material is proportional to
  

(A) square of the extension
(B) under root of the extension
(C) cube Mot of the extension
(D) extension produced

• Very weak magnetic field produced by brain can be detected by
  

(A) compass
(B) metallic needle
(C) Squids
(D) Liquids

• Voltage gain of the transistor as an amplifier is negative because of
  

(A) input voltage is amplified
(3) phase shift of 180°
(C) output voltage is amplified
(D) phase shift is

• In photoelectric effect, if we increase the frequency of the incident light then of the electrons increased
  

(A) number  
(B) K,E        
(C) P.E                        
(D) frequency

• The converse of pair production is
  

(A) hertz effect
(B) Compton effect
(C) Black Body
(D) annihilation of matter

• For an atom ∆X is given as 5 x 10^-11 m. the electron to remain inside the nucleus then its vibrational velocity should be
  

(A) less than the speed of light
(B) equal to the speed of light
(C) greater than the speed of light
(D) Double than the speed of light

• To shut down the nuclear reactor are inserted into the reactor
  

(A) Uranium rods
(B) Cadmium rods
(C) Plutonium rods
(D) Iron rods

• Curie is large unit which equals to disintegration per second
  

(A) 3.7 x 10¹⁰
(B) 3 x 10⁸
(C) 3.7 x 10⁸  
(D) 3 x 10⁶

• Particles that experience the strong nuclear farce
  

(A) Hadrons
(E) Leptons
(C) Photons
(D) Quarks

SUBJECTIVE
MARKS :68
SECTION-I

QUESTION N0.2 Write short answers any Eight (8) questions of the following :16

• Suppose that you follow an electric laid line due to a positive point charge. Do electric Said and electric potential increase or decrease
• Electric lines of force never cross. Why ?
• Do electrons tend to go to regions of high potential or low potential?
• Why does the resistance of a conductor rise with temperature?
• Do bends in a wire affect it: electrical resistance?
• Is the filament resistance lower or higher in a 500 W, 220 V light bulb than in a 100 W, 220 V bulb?
• If a charged panicle moves in a straight line through some region of space, can you say that the, magnetic field in the regior is zero?
• Can a charge at rest be set into motion by bringing a magnet close to it? Explain
• Why the resistance of an ammeter should be low?
• Does the induced emf always acts to decrease the magnetic flux through a circuit?
• Show that Ԑ and  have the same units
• Can a D.C. motor be turnce into a D.C. generator? What changes are required to be done?

QUESTION N0.3 Write short answers any Eight (8) questions of the following

• Why does motor draw more current when it is over loaded?
• A sinusoidal current has. ms value of 10 ampere. What is the maximum or peak value ?
• How does doubling the frequency affect the reactance of (a) an inductor
• Define reactance of a caper itor ? How does reactance changes with the frequency of A.0
• Distinguish between crystalline and amorphous solids
• What is meant by hysteresis loss. How it is used in the construction of a transformer?
• Give the order of conductivity of (a) Conductors (b) Semi conductors
• Give four applications of a photodiode
• Why a photo diod is operated in reverse biased state ?
• What is the net charge on a n-type or a n-type substance
• Which photon red, greed, blue carries the most (a) energy and (b) Momentum
• Why do not we observe a Compton effect with visible light ?

QUESTION N0.4 Write short answers any Six (6) questions of the following

• Define frame of reference and differentiate an inertial frame from Inertial frame from a non inertial frame
• As a solid is heated and begins to glow, why it appear red first
• What are the advantages of laser light over ordinary light
• List the colour of line speetrn of an excited hydrogen atom
• Define ionization energy what is the ionization energy of hydrogen atom
• Why are heavy nuclci unstable
• What information is revealed by the length and shape of the track of an incident particle in walson cloud chamber?
• What factor make a fusion reaction difficult to achieve
• What are the quarks? Explain briefly

Note: Attempt any THREE questions from this is section: 8 x 3= 24

5(a) State Gauss's Law. Derive relation for electric intensity at a point near an in infinite sheet of charge?  5
(b) The resistance of iron wire at 0°C i ,1 x 10⁴. what is it's resistance at 500°C if the temperature Co-efficient of iron is 5.2 x 10^-3 K1? 3

6(a) State Ampere's circuital law and apply it to calculate die magnetic field due to a current carrying solenoid ? 5
(b) An ideal step down transformer is connected to main supply of 240 V . It is desired to operate a 12 V 30 W lamp. Find the current in the primary and the transformation ratio?

7(a) What is Impedance? Find the Impedance of R.0 series circuit and its phase
(b)A wire of 2.5 m long and cross-sect on area 10^-5 m² is stretched 1.5 mm by a force of 100 N in the elastic region. Calculate the strain hi the wire

8(a) What are Logic gates? Explain the functions of 'OR' Gate and 'AND' Gate
(b) An electron is accelerated through a potential difference of 50 V. Calculate its de-Broglie wave length

9(a) Why is nuclear fission reaction considered as a chain reaction ? How can it be controlled?
(b) Calculate longest wavelength of radiation for the Paschen series (RH = 1.0974 x 10^-1)