Doubtly
@Doubtly · Joined Feb 2021
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- The resistance of a potentiometer wire is 8 Ω and its length is 8 m. A resistance box and a 2 V Data: R = 8 Ω, L = 8 m, E = 2 V, K = 1 µV/mm = 1 × frac10⁻⁶ ~V10⁻³ ~m = 10⁻³ V/m K = V/L=fracE R(R+R_B) L^(prime) where R_B is the resistanc... 1
- Find the equivalent resistance between the terminals F and B in the network shown in the figure below given Applying Kirchhoff’s voltage law to loop FGHF, we get, – 10I1 – 10(I1 – I2) + 10(I – I1) + 10(I – I1) = 0 ∴ – 10I1 – 10I1 + 10I2 + 10I – 10I... 1
- A voltmeter has a resistance of 100 Ω. What will be its reading when it is connected across a cell of emf 2 V Data: E = 2V, r = 20 Ω, R = 100 Ω The voltmeter reading, V = IR V = ( 2/100+20 )100 = 200/120=10/6 = 1.667 V. 1
- A parallel plate capacitor is charged and then isolated. The effect of increasing the plate separation on charge Answer: (D) Constant, increases, decreases Charge: the capacitor is isolated after charging, so the charge has nowhere to go. Q stays consta... 1
- Energy stored in a capacitor and dissipated during charging a capacitor bear a ratio. (A) 1 : 1 Energy stored in a capacitor and dissipated during charging a capacitor bear a ratio 1 : 1 1
- A parallel plate capacitor has circular plates of radius 8 cm and plate separation 1mm. (A) 1.78 × 10⁻⁸ C 2
- If the difference between the radii of the two spheres of a spherical capacitor is increased The capacitance of a spherical capacitor is C = 4πε₀ (a b/b-a) where a and b are the radii of the concentric inner and outer conducting shel... 1
- A metal plate is introduced between the plates of a charged parallel plate capacitor. Suppose the parallel-plate capacitor has capacitance C₀, plates of area A and separation d. Assume the metal sheet introduced has the same a... 1
- The safest way to protect yourself from lightening is to be inside a car. Justify. There is danger of lightning strikes during a thunderstorm. Because trees are taller than people and therefore closer to the clouds above, t... 1
- A capacitor has some dielectric between its plates and the capacitor is connected to a DC source. Assume a parallel-plate capacitor, of plate area A and plate separation d is filled with a dielectric of relative permittivity (dielectric c... 1
- Two charges of magnitudes -4Q and +2Q are located at points (2a, 0) and (5a, 0) respectively. The sphere of radius 4a encloses only the negative charge Q₁ = -4Q. The positive charge Q₂ = +2Q being located at a distance of 5a from the... 1
- A 6 µF capacitor is charged by a 300 V supply. It is then disconnected from the supply and is connected Data: C = 6 µF = 6 × 10⁻⁶ F = C₁, V = 300 V C₂ = 3 µF The electrostatic energy in the capacitor = 1/2 Cv² = 1/2 (6 × 10⁻⁶)(300)² = 3 × 10⁻⁶... 1
- One hundred twenty five small liquid drops, each carrying a charge of 0.5 µC and each of diameter 0.1 m form a bigger Data : n = 125, q = 0.5 × 10⁻⁶ C, d = 0.1 m The radius of each small drop, r = d/2 = 0.05 m The volume of the larger drop being equal to the... 1
- The dipole moment of a water molecule is 6.3 × 10-30 Cm. A sample of water contains 1021 molecules Data: p = 6.3 × 10⁻³⁰ C∙m, N = 10²¹ molecules, E = 2.5 × 10⁵ N/C, θ₀ = θ₁ = 0°, θ = θ₂ = 90° W = pE(cos θ₀ – cos θ) The total work required... 1
- In a parallel plate capacitor with air between the plates, each plate has an area of 6 × 10-3 m2 and the separation Data: k = 1(air), A = 6 × 10⁻³ m², d = 2 mm = 2 × 10⁻³ m,V = 100V, t = 2 mm = d, k₁ = 6, ε₀ = 8.85 × 10⁻¹² F/m (i) The capacitance of the ai... 1
- What is gravitational Potential ? We measure the gravitational potential energy U of a body (1) by assigning U = 0 for a reference configuration (such as the body at a refere... 1
- Due to a single charge at a distance r, Force (F ) α 1/r2, Electric field (E ) α 1/r2 but Potential (V) α 1/ r. At a point a distance r from an isolated point charge, the force F on a point charge and the electric field E both vary as 1/r2, while the p... 1
- Is electrostatic potential necessarily zero at a point where electric field strength is zero? Justify. Electric potential is a scalar quantity while electric field intensity is a vector quantity. When we add potentials at a point due two or mo... 1