Practice Questions

Q29.The modulation index for an A.M. wave having maximum and minimum peak to peak voltages of 14 mV and 6 mV respectively is : (1) 1. 4 (2) 0. 4 (3) 0. 2 (4) 0. 6

Q30.The amplitude of 15 sin(1000 πt) is modulated by 10 sin(4 πt) signal. The amplitude modulated signal contains frequencies of A. 500 Hz B. 2 Hz C. 250 Hz D. 498 Hz E. 502 Hz Choose the correct answer from the options given below JEE Main 2023 (12 Apr Shift 1) JEE Main Previous Year Paper (1) A and B only (2) A and C only (3) A and D only (4) A, D and E only

Q30.The power radiated from a linear antenna of length l is proportional to (Given, λ = Wavelength of wave): (1) λ l (2) ( λl ) 2 (3) l (4) l2 λ2 λ

Q30.A TV transmitting antenna is 98 m high and the receiving antenna is at the ground level. If the radius of the earth is 6400 km, the surface area covered by the transmitting antenna is approximately: JEE Main 2023 (08 Apr Shift 1) JEE Main Previous Year Paper (1) 1240 km2 (2) 3942 km2 (3) 4868 km2 (4) 1549 km2 Q31. 0. 5 g of an organic compound (X) with 60% carbon will produce ×10−1 g of CO2 on complete combustion.

Q30.Match List-I with List-II List-I List-II (Layer of atmosphere) (Approximate height over earth's surface) (A) F1−Layer (I) 10 km (B) D−Layer (II) 170 −190 km (C) Troposphere (III) 100 km (D) E−Layer (V) 65 −75 km Choose the correct answer from the options given below. (1) A– II, B– IV, C–I, D– III (2) A– II, B– IV, C– III, D–I (3) A– III, B– IV, C–I, D– II (4) A– II, B–I, C– IV, D– III

Q30.Match List I with List II List I List II AAttenuation I Combination of a receiver and transmitter Process of retrieval of information from the carrier wave at B Transducer II receiver C DemodulationIII Converts one form of energy into another of strength of a signal while propagating through a DRepeater IVLoss medium JEE Main 2023 (30 Jan Shift 2) JEE Main Previous Year Paper Choose the correct answer from the options given below : (1) A-I, B-II, C-III, D-IV (2) A-II, B-III, C-IV, D-I (3) A-IV, B-III, C-I, D-II (4) A-IV, B-III, C-II, D-I

Q30.In an amplitude modulation, a modulating signal having amplitude of X V is superimposed with a carrier signal of amplitude Y V in first case. Then, in second case, the same modulating signal is superimposed with different carrier signal of amplitude 2Y V. The ratio of modulation index in the two case respectively wil be : (1) 1 : 2 (2) 1 : 1 (3) 2 : 1 (4) 4 : 1

Q30.A message signal of frequency 5 kHz is used to modulate a carrier signal of frequency 2 MHz . The bandwidth for amplitude modulation is: (1) 5 kHz (2) 20 kHz (3) 10 kHz (4) 2. 5 kHz

Q30.For an amplitude modulated wave the minimum amplitude is 3 V , while the modulation index is 60%. The maximum amplitude of the modulated wave is: (1) 5 V (2) 15 V (3) 12 V (4) 10 V

Q30.In satellite communication, the uplink frequency band used is: (1) 420 −890 MHz (2) 5. 925 −6. 425 GHz (3) 76 −88 MHz (4) 3. 7 −4. 2 GHz

Q30.Match List I with List II LIST I LIST II A AM Broadcast I 88 −108 MHz B FM Broadcast II 540 −1600 kHz C Television III 3. 7 −4. 2 GHz D Satellite Communication IV 54 MHz − 590 MHz Choose the correct answer from the options given below: (1) A-II, B-I, C-IV, D-III (2) A-IV, B-III, C-I, D-II (3) A-II, B-III, C-I, D-IV (4) A-I, B-III, C-II, D-IV

Q1. A silver wire has a mass (0. 6 ± 0. 006)g , radius (0. 5 ± 0. 005) mm and length (4 ± 0. 04) cm . The maximum percentage error in the measurement of its density will be (1) 7% (2) 3% (3) 4% (4) 6%

Q1. Identify the pair of physical quantities that have same dimensions: (1) Velocity gradient and decay constant (2) Angular frequency and angular momentum (3) Wave number and Avogadro number (4) Wein's constant and Stephan's constant

Q1. The dimension of mutual inductance is (1) ML2 T−2A−1 (2) ML2 T−2A−2 (3) ML2 T−3A−1 (4) ML2 T−3A−2

Q1. An expression of energy density is given by u = αβ sin( αxkt ), where α, β are constants, x is displacement, k is Boltzmann constant and t is the temperature. The dimensions of β will be (1) [ML2 T−2θ−1] (2) [M0L2T−2] (3) [M0L0T0] (4) [M0L2T0]

Q1. An expression for a dimensionless quantity P is given by P = αβ loge( kTβx ) ; where distance; k is Boltzmann constant and T is the temperature. Then the dimensions of α will be (1) [M0L−1T0] (2) [ML0 T−2] (3) [MLT−2] (4) [ML2 T−2]

Q1. Identify the pair of physical quantities which have different dimensions: (1) Wave number and Rydberg's constant (2) Stress and Coefficient of elasticity (3) Coercivity and Magnetisation (4) Specific heat capacity and Latent heat

Q1. Velocity (v) and acceleration (a) in two systems of units 1 and 2 are related as v2 = m2n v1 and a2 = mna1 respectively. Here m and n are constants. The relations for distance and time in two systems respectively are n2 n3 (1) = m T 2 m3 L1 = L2 and n2m T 1 = T2 (2) L1 = m2n4 L2 and T1 (3) L1 = n2m L2 and T1 = m2n4 T2 (4) n2m L1 = L2 and m2n4 T 1 = T2

Q1. Two vectors A and B have equal magnitudes. If magnitude of A + B is equal to two times the magnitude of → → → → A − B, then the angle between A and B will be (1) cos−1( 35 ) (2) cos−1( 13 ) (3) sin−1( 13 ) (4) sin−1( 35 ) a + −b] = RT; P is pressure, V is volume, R is universal gas constant and 2 V

Q1. A small toy starts moving from the position of rest under a constant acceleration. If it travels a distance of 10 m in t s , the distance travelled by the toy in the next t s will be: (1) 10 m (2) 20 m (3) 30 m (4) 40 m

Q1. A torque meter is calibrated to reference standards of mass, length and time each with 5% accuracy. After calibration, the measured torque with this torque meter will have net accuracy of (1) 15% (2) 25% (3) 75% (4) 5%

Q1. Consider the efficiency of Carnot's engine is given by η = sinαβθ loge kTβx , where α and β are constants. If T is temperature, k is Boltzman constant, θ is angular displacement and x has the dimensions of length. Then, choose the incorrect option. (1) Dimensions of β is same as that of force. (2) Dimensions of α−1x is same as that of energy. (3) Dimensions of η−1 sin θ is same as that of αβ (4) Dimensions of α is same as that of β

Q1. Match List I with List II. List I List II (A) Torque (I) Nms-1 (B) Stress (II) Jkg-1 (C) Latent Heat (III) Nm (D) Power (IV) Nm-2 Choose the correct answer from the options given below: (1) A - III, B - II, C - I, D - IV (2) A - III, B - IV, C - II, D - I (3) A - IV, B - I, C - III, D - II (4) A - II, B - III, C - I, D - IV

Q1. The distance of the Sun from earth is 1. 5 × 1011 m and its angular diameter is 2000′′ when observed from the earth. The diameter of the Sun will be (1) 2. 45 × 1010 m (2) 1. 45 × 1010 m (3) 1. 45 × 109 m (4) 0. 14 × 109 m

Q1. A person moved from 𝐴 to 𝐵 on a circular path as shown in figure. If the distance travelled by him is 60 m, then the magnitude of displacement would be : (Given cos135° = - 0 . 7) (1) 42 m (2) 47 m (3) 19 m (4) 40 m