Simultaneous tripping of the circuit breaker at both ends of a transmission line is achieved by

Carrier current over the power line provides simultaneous tripping of circuit breakers at both ends of the line in one to three cycles.
Thereby high-speed fault clearing is obtained, which improves the power system stability.
The auto-reclosing simultaneous reclosing signal is sent thereby simultaneous (1 to 3 cycles) reclosing of the circuit breaker is obtained.
For simultaneous faults, carrier-current protection provides easy discrimination.

As per answer key "pilot protection" is true but there is mistake the right answer is "none".

Murray loop test is performed on a faulty cable 300 m long. At balance, the resistance connected to the faulty core was set at 15 Ω and the resistance of the resistor connected to the sound core was 45 Ω. Calculate the distance of the fault point from the test end.

Where,
R2 is the resistance connected to the faulty core in ohm
R2 is the resistance of the resistor connected to the sound core in ohm

R1 Distance of fault location (Lx) = R2/(R1 + R2)*(2*L)
= (15/60)*600
= 150 m

A THHN conductor will have 75°C termination on one end and a 60/75°C termination on the other, which ampacity column will be used?

Conductor with 75 °C temperature rating must have ampacity from the 60°C column or the 75°C column.
It is permissible to use the 75°C rating if the installed conductor is rated at least 75 °C.
Because all of the connection points in this example have at least a 75°C rating, the conductor’s ampacity can be based on the 75°C column

મારુતારુંનો ઝગડો હજી ખતમ થયો નથી, ચારપાંચ વર્ષ થઇ ગયા અને રાતદિવસ સાથે ઉઠવા-બેસવાનું તો ચાલુ જ છે. ઉપરોક્ત વાક્યમાં ક્યા ક્યા વ્યાકરણીય સમાસનો ઉપયોગ કરાયો છે?

In underground cables, the electrostatic stress is ___ at contactor surface and ___ at the sheath.

The electrostatic stress in a cable is not uniformly distributed.
The potential gradient is inversely proportional to the distance from the centre of the cable.
Hence, it will be maximum (gmax) at the surface of the conductor and goes on decreasing until it becomes minimum (gmin) at the surface of the sheath.
That means electrostatic stress in the dielectric of a cable is maximum at the surface of the conductor and minimum at the surface of the sheath.

By inserting a plate of dielectric material between the plates of a parallel plate capacitor at constant potential, the energy stored in the capacitor is increased five times. The dielectric constant of the material is

Energy stored by capacitor, Q = ½CV²
Dielectric constant is directly proportional to C and capacitance is proportional to the dielectrical constant