Practice Questions

Q26.Two electric dipoles of dipole moments 1 . 2 × 10-30 cm and 2 . 4 × 10-30 cm are placed in two difference uniform electric fields of strengths 5 × 104 N C-1 and 15 × 104 N C-1 respectively. The ratio of maximum 1 torque experienced by the electric dipoles will be 𝑥. The value of 𝑥 is _____ .

Q27.A 110 V, 50 Hz, AC source is connected in the circuit (as shown in figure). The current through the resistance 55 Ω, at resonance in the circuit, will be _____ A.

Q27.Two 10 cm long, straight wires, each carrying a current of 5 A are kept parallel to each other. If each wire experienced a force of 10−5 N , then separation between the wires is _____ cm.

Q27.In meter bridge experiment for measuring unknown resistance ' S ', the null point is obtained at a distance 30 cm from the left side as shown at point D. If R is 5. 6 kΩ, then the value of unknown resistance ' S ' will be _____ Ω.

Q27.A capacitor of capacitance 500 𝜇F is charged completely using a de supply of 100 V. It is now connected to an inductor of inductance 50 mH to form an LC circuit. The maximum current in LC circuit will be _____ A.

Q27.A closely wounded circular coil of radius 5 cm produces a magnetic field of 37. 68 × 10−4 T at its center. The current through the coil is _____ A . [Given, number of turns in the coil is 100 and π = 3. 14]

Q28.The half life of a radioactive substance is 5 years. After x years a given sample of the radioactive substance gets reduced to 6. 25% of its initial value. The value of x is ____

Q28.In a Young's double slit experiment, an angular width of the fringe is 0. 35° on a screen placed at 2 m away for particular wavelength of 450 nm . The angular width of the fringe, when whole system is immersed in a medium of refractive index 7 , is 1 . The value of α is _____ . α 5

Q29.The energy band gap of semiconducting material to produce violet (wavelength = 4000 Å) LED is _____ eV. (Round off to the nearest integer).

Q29.In a Young's double slit experiment, a laser light of 560 nm produces an interference pattern with consecutive bright fringes' separation of 7 . 2 mm. Now another light is used to produce an interference pattern with consecutive bright fringes' separation of 8 . 1 mm. The wavelength of second light is _____ nm .

Q29.A 8V Zener diode along with a series resistance 𝑅 is connected across a 20 V supply (as shown in the figure). If the maximum Zener current is 25 mA, then the minimum value of 𝑅 will be _____ Ω.

Q30.If the potential barrier across a p −n junction is 0. 6 V. Then the electric field intensity, in the depletion region having the width of 6 × 10−6 m , will be _____ ×105 N C−1

Q1. What will be the projection of vector A = ˆi +ˆj + ˆk on vector B = ˆi +ˆj ? + + (1) √2(ˆi +ˆj ˆk) (2) 2(ˆi +ˆj ˆk) (3) √2(ˆi +ˆj) (4) (ˆi +ˆj)

Q1. Which of the following equations is dimensionally incorrect? Where t =time, h =height, s =surface tension, θ =angle, ρ =density , a, r =radius, g = the acceleration due to gravity, V =volume, p =pressure, W =work done, τ =torque, ϵ =permittivity, E =electric field, J =current density, L =length. (1) W = τθ (2) V = πpa48ηL (3) h = 2 scosρrg θ (4) J = ϵ ∂E∂t

Q1. The velocity of a particle is v = (v0 + gt + Ft2) m s−1 . Its position is x = 0 at t = 0 ; then its displacement after time (t = 1 s) is : (1) v0 + g + F (2) v0 + 2g + F3 (3) v0 + 2g + F (4) v0 + 2g + 3F

Q1. Match List I with List II. List I List II (a) →𝐶- →𝐴- →𝐵= 0 (i) → → → (b) 𝐴- 𝐶- 𝐵= 0 (ii) (c) →𝐵- →𝐴- →𝐶= 0 (iii) (d) →𝐴+ →𝐵= - →𝐶 (iv) Choose the correct answer from the options given below: (1) (a) → ( iv ) , (b) → ( i ) , (c) → ( iii ) , (d) → (ii) (2) (a) → (iv), (b) → (iii), (c) → (i), (d) → (ii) (3) (a) → (iii), (b) → (ii), (c) → (iv), (d) → (i) (4) (a) → (i), (b) → (iv), (c) → (ii), (d) → (iii)

Q2. If E, L, M and G denote the quantities as energy, angular momentum, mass and constant of gravitation respectively, then the dimensions of P in the formula P = EL2M −5G−2 are: (1) [M1L1 T−2] (2) [M0 L1 T0] (3) [M−1L−1T2] (4) [M0 L0 T0]

Q2. A ball is thrown up with a certain velocity so that it reaches a height h. Find the ratio of the two different times of the ball reaching h in both the directions. 3 (1) √2−1 (2) 1 √2+1 3 (3) √3−√2 (4) √3−1 √3+√2 √3+1

Q2. The position, velocity and acceleration of a particle moving with a constant acceleration can be represented by : (1) (2) (3) (4)

Q2. Match List - I with List - II. List - I List - II a Torque i MLT−1 b Impulse ii MT−2 c Tension iii ML2 T−2 d Surface Tension iv MLT−2 Choose the most appropriate answer from the option given below : (1) (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii) (2) (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii) (3) (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii) (4) (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)

Q2. If two similar springs each of spring constant K1 are joined in series, the new spring constant and time period would be changed by a factor: (1) 12 , 2√2 (2) 41 , √2 (3) 14 , 2√2 (4) 21 , √2

Q2. Match List - I with List - II : List −I List −II (a) h (Planck's constant) (i) [MLT−1] (b) E (kinetic energy) (ii) [ML2 T−1] (c) V (electric potential) (iii) [ML2 T−2] (d) P (linear momentum) (iv) [ML2 I−1 T−3] Choose the correct answer from the options given below: (1) (a) →(ii), (b) →(iii), (c) →(iv), (d) →(i) (2) (a) →(i), (b) →(ii), (c) →(iv), (d) →(iii) (3) (a) →(iii), (b) →(ii), (c) →(iv), (d) →(i) (4) (a) →(iii), (b) →(iv), (c) →(ii), (d) →(i)

Q2. An object of mass 𝑚 is being moved with a constant velocity under the action of an applied force of 2 N along a frictionless surface with following surface profile. The correct applied force vs distance graph will be : (1) (2) (3) (4)

Q2. A mosquito is moving with a velocity →v= 0. 5t2ˆi + 3tˆj + 9ˆk m s−1 and accelerating in uniform conditions. What will be the direction of mosquitoes after 2 s ? y-axis (1) tan−1( 23 ) from x-axis (2) tan−1( √856 ) from (3) tan−1( 25 ) from y-axis (4) tan−1( 52 ) from x-axis

Q3. Which of the following is not a dimensionless quantity? (1) Power factor (2) Quality factor (3) Permeability of free space (μ0) (4) Relative magnetic permeability (μr)