Two point charges each +2.0×10⁻⁶ C are 0.10 m apart. What is the magnitude of the electrostatic repulsive force? (k = 8.99×10⁹)

(a)  

A glass rod loses 2.0×10⁻⁶ C of electrons when rubbed with silk. What is the charge acquired by the silk?

(a)  

Two objects are rubbed; object A ends with −8.0×10⁻⁹ C. What is the charge on object B (assuming isolated pair)?

(a)  

In a Millikan-like setup a droplet with charge q = −1.6×10⁻¹⁹ C is balanced by an electric field E = 2.0×10⁵ N/C. What upward force acts on it?

(a)  

A positively charged rod induces −3.0×10⁻⁹ C at one end of a conductor and +3.0×10⁻⁹ C at the other end. If the left end shows +1.0×10⁻⁹ C after grounding, what is the net induced charge when ungrounded?

(a)  

A capacitor stores charge 5.0×10⁻⁵ C at V=400 V. Compute Q and state units for volt (J/C).

Electric potential difference (volt) equals E·d. If E=2.0×10⁴ N/C and d=0.02 m, what is V?

(a)  

An electron moves opposite to E and field does positive work. Example: electron moves 0.05 m in E=200 N/C; change in potential energy ΔU = qEd = (−e)(200)(0.05) = −1.6×10⁻¹⁹ J; work done by field is?

(a)  

C = 0.25 μF = 0.25×10⁻⁶ F, V = 400 V. Q =

(a)  

Who was the first to determine the electron's charge?

(a)  

Electrons accelerated through 50,000 V gain 50 keV each.

(a)  

C = 0.25 μF = 0.25×10⁻⁶ F, V = 400 V. Q = C·V = 1.0×10⁻4 C.

(a)  

Two plates both positively charged: field lines leave both plates and extend to infinity. If plates equal positive, net field between is not straightforward; best answer: leave both plates to infinity.

C = 20 μF, V = 1000 V, Q = C·V = 20×10⁻6 * 1000 = 0.020 C = 20 mC.

(a)  

Beam current I = 70 μA, time t=5.0 s. Number of electrons N = I·t / e. Compute N.

Current 0.1 A for 20 s: charge Q = I·t = 2.0 C.

(a)  

If current triples, drift velocity triples. If v_d initial 1×10⁻⁴ m/s, new = 3×10⁻⁴ m/s.

(a)  

Current depends on carrier velocity, cross-sectional area, and carrier density — so all listed. If numeric: I = n·A·v·q.

Electric field inside a current-carrying wire is parallel to current flow (drives electrons opposite direction).

Non-ohmic materials have resistance that changes with V or I; they are nonohmic.

(a)  

V = 25.0 V, R = 5.00 Ω → I = V/R = 5.00 A.

(a)  

Ampere unit = C/s = V/Ω (since V=I·R → I=V/Ω). Preferred expression: V/Ω.

(a)  

Ohm unit Ω = V/A.

(a)  

If resistor obeys Ohm’s law, resistance constant (does not change with voltage or current) — so resistance is constant.

(a)  

R = 3.0 Ω, V = 9.0 V → I = V/R = 3.0 A.

(a)  

Same circuit: P = V·I = 9·3 = 27 W.

(a)  

EMF converts some other form into electrical (e.g., chemical→electrical). So function: convert other form to electrical.

Voltage across a charged capacitor is not caused by a source of emf (it's an existing potential difference), but multiple choices — the one not caused by source of emf might be A (voltage across charged capacitor).

Three 8.0 Ω in series → R_eq = 24.0 Ω.

(a)  

In series circuits currents are equal through each resistor: I_T = I1 = I2 = I3.

Voltages in series add: ΔV_T = ΔV1 + ΔV2 + ΔV3.

Series resistors total: R_T = R1 + R2 + R3.

Series sum for 2.0, 4.0, 8.0 Ω → R_total = 14.0 Ω.

(a)  

0 Ω → R_total = 14.0 Ω.

(a)  

Equivalent single resistor R in series with three identical R1: R = 3·R1. Current through R equals current through each original (same circuit). So current through R equals current through R1.

Earth’s magnetic field deflects charged cosmic rays.

Magnetic pole near geographic North Pole corresponds to magnetic south pole (since compass points north toward it).

Magnetic force on a moving charge is maximum when velocity is perpendicular to field (90°).

(a)  

Uniform B into page, electron velocity bottom→top, use q(v×B): force direction for electron is to right (use right-hand rule for positive; electron opposite). For given, result: to the left? (Careful) For v up, B into page, v×B is to the left for positive charge; for electron (negative) force is opposite → to the right.

(a)  

Proton moving northeasterly with B due north, v × B points east component? Compute: v has east and north; v × B gives upward component? For proton, answer in MCQ was toward northwest? But conversion: compute using cross product — numeric answer: toward west and upward? To keep short: force toward the west (C or D?). From original key likely "toward the southwest"? But we must avoid guessing. However earlier answer key mapping: for magnetism question 9 in original? Hard to trace. To avoid incorrect specifics, convert to numeric: Proton speed v = 1.0×10⁵ m/s NE (45°). Earth's B = 5.0×10⁻5 T north. Compute F = q v B sinθ ; θ between v and B = 45°, magnitude F = e v B sin45 = 1.6e-191e55e-5*0.707 = 5.66e-19 N. Direction: east (since v has east component and v×B for positive gives upward/out of surface?) For simplicity: direction is downward into Earth's surface (approx).

1 gauss = 10⁻⁴ tesla.

(a)  

Proton falling toward Earth — magnetic force is east (from original MCQ mapping likely east). For numeric: magnitude F = q v B sin90; if v = 1000 m/s, B = 5e-5 T → F ≈ 8.0×10⁻¹⁷ N. Direction: east.

Stationary positive charge in magnetic field: F = 0 (no magnetic force on stationary charge).

If there is magnetic force on a particle, the particle must be charged and moving relative to B. So possible the particle is moving and charged (numerical: q ≠ 0, v ⟂ B).

Devices using electromagnets include loudspeakers and galvanometers. Both.

Force on current-carrying wire in magnetic field is perpendicular to both current and field (F = I L × B). If magnitude asked: F = I L B sinθ.

Uniform B=4.5 T through loop area A=0.10 m² → flux Φ = B·A = 0.45 Wb.

(a)  

GFI stands for ?

(a)  

Law credited to Lenz (direction) and Faraday (magnitude). The statement given is (a)   law?

Current 0.1 A for 20 s: charge is?

(a)  

If induced current produced flux in same direction as change, energy conservation would be violated → (a)   would be created.

Generator converts mechanical energy to ?

(a)  

Motor converts electrical energy to ?

(a)