Practice Questions

Q17.A single slit of width a is illuminated by a monochromatic light of wavelength 600 nm . The value of a for which first minimum appears at θ = 30o on the screen will be : (1) 1. 2 μm (2) 3 μm (3) 1. 8 μm (4) 0. 6 μm

Q17.An electric dipole of dipole moment is 6. 0 × 10−6 C m placed in a uniform electric field of 1. 5 × 103 N C−1 in such a way that dipole moment is along electric field. The work done in rotating dipole by 180° in this field will be_______ mJ.

Q17.A cell of emf 90 V is connected across series combination of two resistors each of 100 Ω resistance. A voltmeter of resistance 400 Ω is used to measure the potential difference across each resistor. The reading of the voltmeter will be: (1) 40 V (2) 45 V (3) 80 V (4) 90 V

Q17.With the help of potentiometer, we can determine the value of emf of a given cell. The sensitivity of the potentiometer is (A) directly proportional to the length of the potentiometer wire (B) directly proportional to the potential gradient of the wire (C) inversely proportional to the potential gradient of the wire (D) inversely proportional to the length of the potentiometer wire Choose the correct option for the above statements: (1) B and D only (2) A and C only (3) A only (4) C only

Q17.In a Young’s double slit experiment, the ratio of amplitude of light coming from slits is 2 : 1. The ratio of the maximum to minimum intensity in the interference pattern is (1) 9 : 4 (2) 25 : 9 (3) 2 : 1 (4) 9 : 1

Q17.Different combination of 3 resistors of equal resistance R are shown in the figures. The increasing order for power dissipation is: (A) (B) JEE Main 2023 (13 Apr Shift 1) JEE Main Previous Year Paper (C) (D) (1) PB < PC < PD < PA (2) PC < PD < PA < PB (3) PC < PB < PA < PD (4) PA < PB < PC < PD

Q17.A wire of resistance 160 Ω is melted and drawn in a wire of one-fourth of its length. The new resistance of the wire will be (1) 16 Ω (2) 10 Ω (3) 640 Ω (4) 40 Ω

Q17.Ratio of thermal energy released in two resistor R and 3R connected in parallel in an electric circuit is : (1) 3 : 1 (2) 1 : 1 (3) 1 : 3 (4) 1 : 27

Q17.A uniform metallic wire carries a current 2 A, when 3. 4 V battery is connected across it. The mass of uniform metallic wire is 8. 92 × 10−3 kg, density is 8. 92 × 103 kg m−3 and resistivity is 1. 7 × 10−8 Ω −m The length of wire is : (1) l = 6. 8 m (2) l = 10 m (3) l = 5 m (4) l = 100 m

Q17.The number of turns of the coil of a moving coil galvanometer is increased in order to increase current sensitivity by 50%. The percentage change in voltage sensitivity of the galvanometer will be : (1) 100% (2) 50% (3) 75% (4) 0% JEE Main 2023 (31 Jan Shift 2) JEE Main Previous Year Paper

Q18.If the potential difference between B and D is zero, the value of x is n1 Ω. The value of n is ______.

Q18.In the given circuit, the equivalent resistance between the terminal A and B is ____ Ω

Q18.Consider the following radioactive decay process: 𝛼 𝛽- 𝛾 𝛼 𝛽+ 𝛾 218𝐴84 ⟶𝐴1 ⟶𝐴2 ⟶𝐴3 ⟶𝐴4 ⟶𝐴5 ⟶𝐴6 The mass number and the atomic number of A6 are given by: (1) 210 and 82 (2) 210 and 84 (3) 210 and 80 (4) 211 and 80

Q18.The number density of free electrons in copper is nearly 8 × 1028 m−3 . A copper wire has its area of cross- section = 2 × 10−6 m2 and is carrying a current of 3. 2 A . The drift speed of the electrons is _____ ×10−6 m s−1 .

Q18.A capacitor has capacitance 5 µF when its parallel plates are separated by air medium of thickness d. A slab of material of dielectric constant 1. 5 having area equal to that of plates but thickness d2 is inserted between the plates. Capacitance of the capacitor in the presence of slab will be ______ µF .

Q18.If each diode has a forward bias resistance of 25Ω in the below circuit, Which of the following options is correct? (1) I1 = 1 (2) I2 = 1 I2 I3 I1 I3 (3) = 2 (4) = 1 I2 I4

Q18.The current flowing through a conductor connected across a source is 2 A and 1. 2 A at 0oC and 100oC respectively. The current flowing through the conductor at 50oC will be _____ × 102 mA .

Q18.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : The binding energy per nucleon is practically independent of the atomic number for nuclei of mass number in the range 30 to 170. Reason R : Nuclear force is short ranged. In the light of the above statements, choose the correct answer from the options given below (1) A is false but R is true (2) Both A and R are true and R is the correct explanation of A (3) Both A and R are true but R is NOT the correct (4) A is true but R is false. explanation of A

Q18. The current flowing through R2 is : (1) 3 2 A (2) 12 A (3) 1 3 A (4) 14 A

Q18.The mass of proton, neutron and helium nucleus are respectively 1 . 0073 u, 1 . 0087 u and 4 . 0015u. The binding energy of helium nucleus is: (1) 14 . 2 MeV (2) 28 . 4 MeV (3) 56 . 8 MeV (4) 7 . 1 MeV

Q18.If a copper wire is stretched to increase its length by 20% . The percentage increase in resistance of the wire is _____%.

Q18.A potential V0 is applied across a uniform wire of resistance R. The power dissipation is P1. The wire is then cut into two equal halves and a potential of V0 is applied across the length of each half. The total power dissipation across two wires is P2. The ratio of P2 : P1 is √x : 1. The value of x is _____.

Q18.A free neutron decays into a proton but a free proton does not decay into neutron. This is because (1) neutron is an uncharged particle (2) proton is a charged particle (3) neutron is a composite particle made of a proton (4) neutron has larger rest mass than proton and an electron

Q18.A student is provided with a variable voltage source V , a test resistor RT = 10Ω , two identical galvanometers G1 and G2 and two additional resistors, R1 = 10MΩ and R2 = 0. 001Ω . For conducting an experiment to verify ohm's law, the most suitable circuit is: (1) (2) (3) (4) JEE Main 2023 (06 Apr Shift 2) JEE Main Previous Year Paper

Q18.The H amount of thermal energy is developed by a resistor in 10 s when a current of 4 A is passed through it. If the current is increased to 16 A , the thermal energy developed by the resistor in 10 s will be (1) H (2) 16H (3) H (4) 4H 4