EE MCQ

SSC JE Electrical 2019 with solution SET-1
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In electric traction, the coefficient of adhesion is represented by

When two solid surfaces are brought into contact, a finite normal force is needed to pull the two solids apart. This force is known as the force of adhesion or simply adhesion.

The coefficient of adhesion () defined as the ratio of tractive effort required to propel the wheel of a locomotive to its adhesive weight. Adhesion traction is the friction between the drive wheels and the steel rail.

µ = Ft/W

Where

Ft = Tractive effort

W = Adhesive Weight

Related Question

SSC JE Electrical 2019 with solution SET-1
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________ is used to manufacture stay wire, earth wire, and structural components

Galvanized steel conductors do not corrode, and possess high resistance. Hence such Wires are used in telecommunications circuits, earth wires, guard wire, stray wire, etc.

SSC JE Electrical 2019 with solution SET-1
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In the two wattmeter method, the readings of the two wattmeters are 500W, 500W respectively. The load power factor in a balanced 3-phase 3-wire circuit is:

In two wattmeter method the phase angle is tanφ = √3(W1 − W2)/(W1 + W2) tanφ = √3(500 − 500)/(500 + 500) tanφ = 0° φ = tan−10° = 0° Power factor = cosφ PF = cos0° = 1

SSC JE Electrical 2019 with solution SET-1
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An electric heater is connected across 230V and it draws a current of 2A. Then the resistance offered by the heater is?

Given

Voltage V = 230 V

Current I = 2 A

Resistance R = V/I

R = 230/2 = 115 Ω

SSC JE Electrical 2019 with solution SET-1
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Identify the important feature of a DC series motor

In DC series motor Torque (Ta) increase as the Square of armature current (Ia) Ta ∝ Ia2. So DC motor provides high starting torque.