MCQ ANSWER KEY 3 4 5 6 7 8 9 D A D B D C B B C A CHEMSTRY ANSWERS Explanation According to Graham s Law we can arrange gasses amount in the container B A molecule with high molecular masses has a trace amount in gas mixture in container D Graham s Law The rates of effusion o two different gases are inversely proportional to the square roots of their molar masses The answer is D NH 3 + HCl NH 4 Cl 4/7=53 mol (NH 3 ) 4/3645=mol (HCl) The mol of excess ammonia: 353-=556 mol Area of circle: S=πr =34x5 = 7854 cm Volume of the cylinder: V=Sh=7854x6=56637 cm 3 = 57 L f the stopcock is opened the total volume: x 57 L=533 L Now we can use ideal gas equation for calculation of final pressure: PV=nRT/ P 533= 8 98/ P= atm The answer for this question is A 3 Zn + +e - Zn/x96485 =335946 coulomb is needed for deposited mol Zn
65g Zn-----------335946 coulomb 45g Zn----------x coulomb x=335946 coulomb Q= t/ 335946 coulomb=35-3 t/t=335946 seconds=63 hours The answer for this question is D 4 Potassium carbonate and ammonium sulfate gave precipitate with barium nitrate solution The medium of ammonium sulfate is acidic Potassium carbonate solution s basic medium and basic solutions turn color of phenolphthalein solutions into pink, so the answer for this question is B 5 Sucrose is non electrolyte (3), KNO 3 is strong electrolyte (), NH 3 and CH 3 COOH are weak electrolytes () The answer is, D) -, -3, -, V- 6 The MM of NaF=4 g/mol We can find the mol of NaF in the given solution and we calculate the mass of NaF in the solution ml=l, (volume of the solution), 5=x/, x= mol The mass of NaF: *4=4 The answer is C 7 The position of metals shown in the periodic table given below; Li Na Ca Sr Atomic radius increases from the top to the bottom According to this picture we can arrange the following increasing order of atomic size for metals The answer is B) Li<Na<Ca<Sr
8 High ionization and poor conductivity related to non-metals So the answer is B 9 344 grams of CaSO 4 n H O--------------46668 grams of BaSO 4 is formed X grams of CaSO 4 n H O----------------- 33 g/mol BaSO 4 is formed X=775 grams/mol of hydrate is formed X=775 grams/mol-36 grams/moles of CaSO4=3575 grams of water is formed 3575/8= moles of water, n= The answer is C % of apple is fructose, so *86=3 g 3 4 5 6 7 8 9 A C B C D A B C D C 8 g/mol fructose ----------------------release 8 kj/mol energy 3 g fructose-----------------------release x kj energy X= (3*-8)/8=63 kj=63 J/484=38538 cal=3853 kcal The answer for this question is A PHYSCS ANSWERS Explanation Since the total resistance of the ring is R, the resistance of an arc spanning the angle α is Similarly the resistance of the second arc will be R thus the total resistance is R = R R R + R = R ( ) Rα π α = 4π ( π α ) π Rα R = π The two resistors are connected in parallel, 3
The current measured by the ammeter will be ε 4επ = = R Rα π α ( ) The graph at choice A corresponds to this equation Correct answer: (A) The heat delivered by the heater will be solely used to increase the temperature of the objects For the first object Pt = mc T and similarly for the second one Pt = mc 3 T From these equations we obtain that 3c t t = c = 75 mins Correct answer :(С) 3 The motion of the object is described in the diagram below υ o υ υ = m/s L L Object will acquire the maximum velocity just before it starts to decelerate The relationship between maximum and initial velocity can be obtained from the kinematic relation υ = υ + al Afterwards the object will decelerate to stop υ = al Combining the two equations the acceleration can be written in terms υ of the initial velocity and the mentioned distances a = L ( L ) The maximum velocity is obtained from the last two equations to be υ max = υ L L L = υ k k Correct answer: (B) 4 The critical angle for this material is β = n = sin = 358 4
The light will undergo total internal reflection as long as the angle is greater than this The initial angle of refraction is calculated from the Snell s law sin 7 = 5 sinα α = 8 The light path inside the prism is described in the diagram below The light will make 3 total internal reflections At the 4 th incidence, the angle will be less than the critical angle and the light will be able to escape the prism Correct answer :(С) 5 The acceleration of the object is computed from the given graph to be υ m a = = 5 s t From the Newton s second law the equation for the acceleration is deduced to be a = g(sinα f cosα) Substituting the value of the acceleration found from the graph we obtain the angle of inclination to be α = 86 Correct answer:(d) 6 Correct answer: (A) 7 The problem is similar to a collision problem where we can write the conservation of momentum m υ + M υ = ( m + M ) υ The relationship between the masses of the cart and the child will then be M = 4m Correct answer: (B) 5
8 The readings of the ammeters and the voltmeters in the two configurations are = 5A = A V V = 3V = 6V For the circuit being studied, relationship between the readings of the ammeters and the voltmeters is V = ε r V = ε r Canceling the internal resistance of the battery from the equations we end up with ε V = ε V From here the EMF of the battery is calculated to be ε = 3 8 Volt Correct answer : (C) 9 Before collision After collision Velocity of ball relative to the large truck is u+v before collision After collision relative velocity must be same Therefore u = u+v Correct answer: (D) From the diagrams given in the content of the question we obtain that, the center of mass is at G 6
The distances from the edges to the center of mass are GP= 4 GQ= 3 GR= 7 GS= 5 GT= 8 The potential energy will be maximum when the center of mass of the object is at its highest position, ie when it is hanged from Q And the potential energy is minimum when the center of mass of the object is at its lowest position, ie when it is hanged from S Correct answer: (C) 3 4 5 6 7 8 9 3 B C A D D B C C B B BOLOGY ANSWERS 7