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The frequency for which a 5 μF capacitor has a reactance of 1/1000 ohm is given by
If the instantaneous current in a circuit is given by: I = 2cos(ω t + φ)A, then r.m.s. value of the current is
In which of the following systems will the radius of the first orbit (n = 1) be minimum
A ball weighing 10 g hits a hard surface vertically with a speed of 5 ms⁻^{1} and rebounds with the same speed. The ball remains in contact with the surface for 0.01 s. The average force exerted by the surface on the ball is
A dipole of dipole moment p̅ is placed in uniform electric field E̅, then torque acting on it is given by
In a certain 0.1m^{3} of space, electric potential is found to be 5V throughout. The electric field in this region is
A ball of mass 0.25 kg attached to the end of a string of length 1.96 m is moving in a horizontal circle. The string will break if the tension is more than 25 N. What is the maximum speed with which the ball can be moved?
Given,
Length of String, l = 1.96m
Mass of Ball, m = 0.25 Kg
Maximum Tension of String, T_{max} = 25 N
Let the speed of the balls is v m/s
In the horizontal circular motion of the ball tension in the string is balanced by the centrifugal force (mv^{2}/l) and hence the maximum tension in the string will be for the maximum speed of the ball (since m and l are fixed)
Therefore,
Therefore, maximum speed of the ball will be 14 m/s
A ball of mass m strikes elastically a wall at an angle of 30º with velocity ν. The change in momentum is
A current passing through a circular coil of two produces a magnetic field of 8 T at its centre. The coil is then rewound, so as to have four turns and current is passed through it is doubled. Now magnetic field at the centre of the coil will be
The following figure shows a logic gate circuit with two inputs A and B and the output C. The voltage waveforms of A, B and C are as shown below.
The logic circuit gate is
Sixty four spherical rain drops of equal size are falling vertically through air with a terminal velocity 1.5 ms⁻^{1} If these drops coalesce to form a big spherical drop, then terminal velocity of big drop is
An aeroplane is flying horizontally with a velocity of 600 km/h and at a height of 1960 m. When it is vertically at a point A on the ground, a bomb is released from it. The bomb strikes the ground at point B. The distance AB is
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer
Assertion(A): When charges are shared between two bodies, there occurs loss of energy.
Reason(R): In case of sharing of charges, conservation of energy fails.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer
Assertion(A): For refraction in a plane surface v can be used for the light moving from μ_{1} to μ_{2}.
Reason(R): for light getting into a medium of index μ_{2} from μ_{1}.
Number of particles emitted in the reaction is
According to the Bohr model, electrons of quantum number n = 4 in excited hydrogen atoms can undergo transitions to lower energy states in different ways and give rise to photons of discrete frequencies. How many discrete frequencies are possible in this case?
A parallel plate capacitor with air between the plates has a capacitance of 9 pF. The separation between its plates is 'd' . The space between the plates is now filled with two dielectrics. One of the dielectrics has dielectric constant K_{1} = 3 and thickness d 3 while the other one has dielectric constant K_{2} = 6 and thickness. 2d 3 Capacitance of the capacitor is now
The angular speed of an engine wheel making 90 revolutions per minute is
An electron moves in a circular orbit with a uniform velocity v. It produces a magentic field B at the centre of the circle. The radius of the circle is proportional to
Two identical conducting spheres, each of radius R, carry charges +Q and Q/2 respectively. When the distance between their centres is d(d > 2R), the attractive force between them is F. The spheres are now brought into contact and then separated to the initial distance d. The force between the spheres is now
3 moles of ethanol react with one mole of phosphorus tribromide to form 3 moles of bromoethane and one mole of X. Which of the following is X?
When formaldehyde and KOH are heated we get,
An equilibrium mixture for the reaction
2A_{2}B_{(g)} ⇌ 2A_{2(g)} + B_{2(g)} had 0.5, 0.1 and 0.4 moles of A_{2}B, and A_{2} and B_{2} in a two litre vessel respectively the equilibrium constant (K) is__
In a reaction : A → B, the rate of reaction, increases two times, on increasing the concentration of reactants four times. Then, order of reaction is
Calculate the difference between the Δ E AND Δ H for the following reaction at 2º C (in K.cal)
R = 2 cals/degmole
T = 27 º C = 27 + 273 = 300 º A
Δ n = No of moles of gaseous products  No of moles of gaseous reactants = 23=1
Δ H = Δ E + Δ n R T
Δ H − Δ E = Δ n R T = − 1 x2 x300 = − 600 cals = − 0.6 K . c a l .
Which pair of elements of atomic numbers given below will have similar chemical properties?
In the periodic table, the elements belong to the same group have similar chemical properties. Atomic number3 (i.e. Li ) and atomic number11 (i.e. Na ) belong to the same group (i.e. alkali metals), thus they have similar chemical properties.
Which of the following is orgnometalic compound?
Which of the following compound gives dye test ?
When HCl gas is passed through a saturated solution of common salt, pure NaCl is precipiated because
The electrode potentials of halfcell reactions are: Zn → Zn^{2}⁺ + 2e⁻ ; E = 0.76 V and Fe → Fe^{2⁺} + 2e⁻ ; E=0.41 V. The e.m.f. of the cell Fe^{2}⁺ + Zn → Zn^{2}⁺ + Fe is
Which of the following will act as Lewis base, nucleophilic reagent as well as ligand in complex compound ?
Sodium carbonate cannot be used in place of ammonium carbonate for the identification of the fifth group radicals . This is because the
Which of the following isomers will have the highest octane number ?
A solid has a structure in which in which 'W' atoms are located at the corners of a cubic lattice, 'O' atoms at the centre of edges and 'Na' atoms at the centre of the cube. The formula for the compound is
Bodycentred cubic has coordination number of
The lowering in vapour pressure, caused by the addition of 100 g of surcose (molecular weight = 342) in 1000 g of water, if the vapour pressure of pure water at 25ºC is 23.8 mm of Hg, is
A 0.6% solution of urea (molecular weight = 60) would be isotonic with
For a d electron,the orbital angular momentum is :
Which shell would be the first to have a g subshell?
For g subshell, l = 4. Minimum n should be 5.
Given : C + 2S→CS₂ ; ∆H = 117 KJ
C + O₂→CO₂; ∆H = 393 KJ
S + O₂→ ; ∆H = 297 KJ
The heat of combustion of CS₂ to form CO₂ and SO₂ is
The equation for an overall reaction is M+ 2N → X + Y; therefore, the rate equation for this reaction is__
No concentrations of reactants and products are given at different intervals of time.
The oxidation number of the central metal ion in Wilkinson's catalyst is__
Wilkinson's catalyst is [(Ph_{3}P)_{3}RhCl]
The Beilstein test for organic compounds is used to detect
The number of real solution of the equation x^{2}  3∣x∣ 2 = 0 is :
If 'n' is a positive integer, then n^{3} + 2n is divisible by
the area of the ellipse x^{2}/a^{2} + y^{2}/b^{2} = 1 is
The locus of the points from which the lengths of the tangents to the two circles x^{2} + y^{2} + 4x + 3 = 0, x^{2} + y^{2}  6x + 5 = 0 are in the ratio 2:3 is a circle with centre
The equation of the circle described on the common chord of the circles x^{2} + y^{2}8x + y 15 = 0 and x^{2}+ y^{2 } 4x + 4y  42 = 0 as diameter is
The locus represented by z  1 = z + i is
The solution of the differential equation cos(x + y)dy = dx is
Let f : Z → Z be defined as f x = x^{2} , x ∈ Z. The function f is
Ajay runs a mile in 8 minutes. At this rate how long will it take him to run a 26mile marathon?
Which of the following problems can be solved using the same arithmetic operations that are used to solve the problem above?
Ajay runs one mile in 8 minutes, so you’d have to multiply 8 by 26 to get the minutes it would take him to run the 26 miles at the same rate. The arithmetic operation used to solve this problem is multiplication.
In choice A, you’d have to divide the 220 minutes by 26 to get the time for one mile. For choice B, the total number of books would have to be divided by the number of shelves to get the books per shelf. Finally, in choice D, to find the number of baskets you’d have to divide the 500 grams by 60. But to figure out choice C, the weight of one box of crackers, 200 grams, would have to be multiplied by 100 to find the weight of all the boxes. Only in choice C would you have to multiply, as in the questions
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer
Assertion(A):The determinants are not identically equal.
Reason(R): If two rows (or columns) of a determinant are identical, then value of the determinant is zero.
The system of equations x+y+z=6, x+2y+3z=10. x+2y+λz=12 is inconsistent, if
In the following question, a Statement1 is given followed by a corresponding Statement2 just below it. Read the statements carefully and mark the correct answer
Statement1:
The curve is symmetric with respect to the line x = 1.
Statement2:
A parabola is symmetric about its axis.
Axis of the parabola x^{2} − 3 y − 6 x + 6 = 0 is
A polygon has 44 diagonals. The number of its sides is
A pair of dice is thrown and the numbers appearing have sum greater than or equal to 10. The probability of getting 10 is
The plane XOZ divides the join of (1, 1, 5) and (2, 3, 4) in the ratio λ : 1, then λ is
Which of the following is not a measure of central tendency?
The equation of line passing through (c,d) and parallel to ax+by+c=0 is
Angle of intersection of the curves y=4x^{2 }and y=x^{2} is
The one root of the equation cos xx+(1/2)=0 lies in the interval
The unit normal vector to the line joining ij and 2i+3j towards origin is
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer
Assertion(A):
Reason:
If x + y = 12, then the minimum value of x^{2} + y^{2} is
Consider an infinite series with first term 'a' and common ration 'r'. If it sum is 4 and the second term is 3/4, then
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