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A parallel plate capacitor with width 4 cm, length 8 cm and separation between the plates of 4 mm is connected to a battery of 20 V. A dielectric slab of dielectric constant 5 having length 1 cm, width 4 cm and thickness 4 mm is inserted between the plates of parallel plate capacitor. The electrostatic energy of this system is ____ ε0. (Where ε0 is the permittivity of free space)

1. 240.00
2. 240
3. 240.00 ε0
4. 240 ε0

Correct answer: 240.00

Solution

The correct option is right because the electrostatic energy stored in a capacitor is calculated using the formula U = 1/2 CV², where C is the capacitance. In this case, the presence of the dielectric slab increases the capacitance, and after calculating the energy with the given dimensions and dielectric constant, the result is 240.00 ε0.

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