General Questions and Answers

004 each 11 An object of height 7 5 cm is placed in front of a convex mirror of radius of curvature 25 cm at a distance of 40 cm The height of the image should be 1 2 3 cm 2 1 78 cm 3 1 cm 4 0 8 cm

2003 rat a mage REFLECTION AT SPHERICAL SURFACE 10 The focal length of a concave mirror is 50 cm where an object be placed so that its image is two times magnified real and inverted 1 75 cm 2 72 cm 3 63 cm 4 50 cm G00010

to each s Then 6 00003 ror at a s image 1 5 10 3 7 4 8 GO0009 REFLECTION AT SPHERICAL SURFACE The focal length of a concave mirror is 50 cm where an object be placed so that its image is two times magnified real and inverted 1 75 cm 2 72 cm 3 63 cm 4 50 cm 600010

Critical temperature and critical pressure value of four gases are given Gas Critical Temp K P Q R S 5 1 33 Critical Pressure atm 2 2 13 34 40 Which of the following gas es cannot be liquefied at a temperature 100 K and pressure 50 atm A S only B P only C R and S D P and Q X D 126 135

Laws of Motion 89 21 A block of weight Wis supported by three strings as shown in figure Which of the following relations is true for tension in the strings Here T T and T are the tension in the strings A B and Crespectively 135 A C W

3 May be true 4 May be false 5 Two blocks of mass M and m are kept on the trolley whose all surfaces are smooth select the correct statement F M M m 1 If F 0 blocks cannot remain stationary 2 For one unique value of F blocks will be stationary 3 Blocks cannot be stationary for any value of F because all surfaces are smooth

3 A metallic chain 1m long lies on a horizontal surface of a table The chain starts sliding on the table if 25 cm or more of it hangs over the edge of a table The correct value of the coefficient of friction between the table and the chain is 1 3 2 4 23115 58 A fro ro the 1 2 3 4

1 A heavy box is slid across a rough floor with an initial speed of 4 m s It stops moving after 8 seconds If the average resisting force of friction is 10 N the mass of the box in kg is 1 40 2 20 3 4 25

1 Mg sin 9 uMg cos 0 2 Mg sin 8 uMg cos 0 3 Mg sin 0 4 Mg cos 0 20 Figure shows two block system 4 kg block rests on a smooth horizontal surface upper surface of 4 kg is rough A block of mass 2 kg is placed on its upper surface The acceleration of upper block with respect to earth when 4 kg mass is pulled by a force of 30 N is 1 6 m s 2 kg 74 kg 0 8 14 0 6 30 N 2 5 m s 2

3 T T 4 T T T 2 A car accelerates on a horizontal road due to force exerted by 1 The engine of the car 2 The driver of the car 3 The earth as weight of the car 4 The road

If Cl O7 is 40 dissociated at 60 C then what will be the rate of diffusion at 60 C compared to undissociated state C1 0 g C g 0 9 1 7 2 3 7 1 2 1

18 A block of 10 kg mass is placed on a rough inclined surface as shown in figure The acceleration of the block will be 1 Zero 6 22 10 kg 30 H 1 10 8 2 g 3g 2

18 1 t Bu ild Up Your Understanding A man is 180 cm tall and his eyes are 10 cm below the top of his head In order to see his entire height right from toe to head he uses a plane mirror kept at a distance of 1 m from him The minimum length of the plane mirror required is 1 180 cm 2 90 cm 3 85 cm 4 170 cm GO0008

1 180 cm 2 90 cm 3 85 cm 4 170 cm GO0008 Two plane mirrors are at 45 to each other If an object is placed between them then the number of images will be 1 5 2 9 3 7 4 8

Board Competitive Exams 17 Figure shows two blocks connected by a light inextensible string as shown in figure A force of 10 N is applied on the bigger block at 60 with horizontal then the tension in the string connecting the two masses is 2 kg 3 kg Smooth surface 10N 60

8 The maximum speed with which a vehicle can take safely circular turn on a horizontal flat rough road is whe symbols have their usual meanings 1 rg 3 rg rg 2 14 4 rgu

68 Two particles each of mass mare moving in horizontal circle with same angular speed If both string are of sam length then the ratio of tension in string 3 2 3 2 2 3 1 3

O 4 4 g of CO and 2 24 litre of H at STP are mixed in a container The total number of molecules present in the container will be 1 6 023 1023 3 6 023 1022 k 1 2046 1023 4 6 023 1024

Which of the following has the maximum de Bregtie wavelength A photoelectron travelling with KEmax ejected from a metal plate p 2 eV when incident with a radiation of wavelength 155 nm An a particle mass 4 x mass of a proton travelling at 104 m s A man m 66 kg running at 6 kmph A ball m 330 a with a velocity of 150 A

58 If trolley accelerates horizontally with acceleration a then bob is displaced backward from its initial vertical positio The angular deflection of the bob in equilibrium is 1 0 cos 3 0 cot m O O 2 0 sin 4 8 tan

01 Which of the following contains the greatest number of atoms 1 0 g butane C H 2 1 0 g of nitrogen N 2 1 0 g of water H O 3 1 0 g of sulphur S 17 8

Which of the following pairs have the same number of molecules i 2 g of 0 4 g of SO2 ii 2 g CO 2 g of N O iii 224 ml O at STP 448 ml of He at 0 5 atm and 273 K iv 2 g oxygen and 2 g ozone Onlyi Onlyiii iiiiandiv

3 53 A vehicle is moving on a road with an acceleration a 20 m s as shown in figure The frictional coefficient between the block of mass m and the vehicle so that block is does not fall downward is g 10 m s a 20 m s 1 0 5 2 0 4

67 In a conical pendulum the length of string is and 0 is the angle of string with vertical The time period of revolution is 1 2n 3 2n g cose 2 2 Icose 4 Infinite

Element X shows diagonal similarity with element Y Oxide of X in fused condition when mixed with Na2CO3 produces many different types of compounds of X The fluoride of Y is triangular planar and forms an adduct with NH3 Which is incorrect for X Y or their compounds 6n X4011 has atleast two oxygen shared per tetrahedral unit OH3YO3 is a weak monobasic acid in aqueous solution XO has 3 D network structure YN S has structure identical to Benzene is called Inorganic Benzene

17 1 0 57 3 0 5 10 kg 20 kg 1 0 5 2231 OFT 2 0 75 4 None of these 45 Smooth 45 rough The ratio of acceleration of blocks A placed on smooth incline with block B placed on rough incline is coefficient of kinetic friction between block B and incline is 2 0 75 of the

48 A block of mass 10 kg moving with acceleration 2 m s on horizontal rough surface is shown in figure a 2 m s 22 40 N The value of coefficient of kinetic friction is 1 0 2 E 2 0 4 04

3 36 Block of mass 10 kg is moving on inclined plane with constant velocity 10 m s The coefficient of kinetic frict between incline plane and block is 37 1 0 57 3 0 5 10 kg 20 kg 10 m s 2 0 75 4 None of these

In the presence of electrical or magnetic field the behaviour of cathode rays are similar to that expected from negatively charged particles suggesting that the cathode rays consist of negatively charged particles called electrons

If the wavelength of electromagnetic radiation is 100 nm then the energy of the quanta will be h 6 625 10 34Js c 3 108 ms O 6 25 10 18 J 3 75 10 19 J 6 625 10 17 J X 1 99 10 18 J

A bivalent a Is pair of synapsed homologous chromosomes b Is also called tetrad c Includes two chromatids only d Includes two non homologous chromosomes O O O O a and b are true a and c are true b and d are true c and d are true

The correct order of decreasing wavelength of the given electromagnetic radiation follows the order O IR Microwave Radiowave

9 Blocks shown in figure moves with constant velocity 10 m s towards right All surfaces in contact are rough The friction force applied by B on A is 20 N A B Ground

ank the following species according to the decreasing energy needed to raise the temperature of 10 f the substance by 25 0 C Rank from most to least energy needed To rank items as equivalent overlap them View Available Hint s copper gold water 27 sodium chloride Reset Help cast iron

41 A block of mass 10 kg is kept on a fixed rough u 0 8 inclined plane of angle of inclination 30 The frictional force acting on the block is 1 3 50 N 52 N 10 kg 30 2 4 50 3 N 54 N

Which of the following is self adjusting in nature 1 Rolling frictional force 3 Kinetic frictional force RAME OF REFERENCE 2 4 All of these Static frictional force

coefficient of kinetic friction between block B and incline is 1 0 5 3 0 57 38 A block of mass 10 kg is released on rough incline plane Block start descending with accelera 2 m s Kinetic friction force acting on block is take g 10 m s 1 10 N 3 2 0 75 4 None of these 50 N 30 2 30 N 4 50 3 N

56 Laws of Motion Board Competitive Exam 34 If acceleration of A is 2 m s which is smaller than acceleration of B then the value of frictional force applied by on A is 5 kg A 10 kg B

Glucose on prolonged heating with Hi giv 1 6 iodohexanal 3 1 Hexene MAINS 201 Which of the following compounds will behave as a reducing sugar in an aqueous KOH solu HOH C CH OH HOH C CH OH 3 HOH C OH OH OH OH O CH OCH 2 n Hexane 4 Hexanoic acid OH 2 4 HOH C OH OH OCH OH OH CH OH OCOCH The formation of which of the following polymers involves hydrolysis reaction MAIN

For the given reaction 12 H S H S s H I Choose the correct statement Olodine is oxidised and hydrogen is reduced O Sulphur is oxidised and hydrogen is reduced O lodine is reduced and sulphur is oxidised O Sulphur is reduced and iodine is oxidised

50 gm of MgCO3 sample decomposes on heating to give magnesium oxide MgO and 11 gm of CO2 Percentage purity of MgCO3 in the sameple is A 42 B 25 20

3 2 2 4 X The sound intensity level at a point 4 m from the point source is 10 dB then the sound level at a distance 2 m from the same source will be 2 16 dB 4 32 dB 1 26 dB 3 23 dB

The degree of dissociation of A is 10 then find molecular weight of A for given reaction when vapour density of mixture is 60 B g C g A g O 120 O 132 O 60 O 66

An ionic bond A B is most likely to be formed when O the ionization energy of A is high and the electron affinity of B is low O the ionization energy of A is low and the electron affinity of B is high O the ionization energy of A and the electron affinity of B is high O the ionization energy of A and the electron affinity of B is low

12 A wave is represented by x 4 cos Br 2 w where x and y are in metre and in second The frequency of the wave in s is 1 3 TKNK 2 2 4 13 A wave in represented by the COK ation

Which of the following has the maximum de Broglie wavelength A photoelectron travelling with KEmax ejected from a metal plate 2 eV when incident with a radiation of wavelength 155 nm O An a particle mass 4 x mass of a proton travelling at 104 m s A man m 66 kg running at 6 kmph A ball m 330 g with a velocity of 150 kmph

Which of the following CI Reaction 1 NaOH 623 K 300 atm Only one correct answer option is true for below conversion Reaction 2 Reaction 3 2 0 CHCI NaOH 340 K A Reaction 1 is called Dow s process B B is phenol and formed via activated nucleophilic substitution C Bis sodium salt of salicylic acid

Extraction of metals of I group is difficult due to i High thermal stability of their compounds ii High reducing power of metals of group I iii Their ability to react with water Only one correct answer A i only B C D i ii only iii only i ii

Dr Hellman has 79 students between his two Intro Chemistry classes Is this a measured or exact number AND how many significant figures are there Exact two significant figures Measured two significant figures Measured unlimited number of significant figures Exact unlimited number of significant figure

A solution of K Cr O7 and sulphuric acid react with H O to produce blue coloured compound X which is soluble in ether and produces blue colour solution Which of the following statements are correct regarding compound X A The oxidation state of Cr in this compound is 6 B This compound has 2 peroxy linkage C The hybridization of Cr in X is sp of D It is strongest base among all compound of chromium Only one correct answer A B C D A and B are correct A B and C are correct A B D are correct A D are correct