Electrolysis and Storage of Batteries

101. The watt-hour efficiency of a lead-acid cell varies between

1. 25 to 35%
2. 40 to 60%
3. 70 to 80%
4. 90 to 95%

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102. Those substances of the cell which take active part in chemical combination and hence produce electricity during charging or discharging are known as _________ materials.

1. passive
2. active
3. redundant
4. inert

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103. Trickle charging of a storage battery helps to

1. maintain proper electrolyte level
2. increase its reserve capacity
3. prevent sulphation
4. keep it fresh and fully charged

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104. Under normal charging rate, the charging current should be

1. 10% of capacity
2. 20% of capacity
3. 30% of capacity
4. 40% of capacity

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105. Undercharging

1. reduces specific gravity of the electrolyte
2. increases specific gravity of the electrolyte
3. produces excessive gassing
4. increases the temperature

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106. Weston standard cell at 20°C has voltage of _________ volts.

1. 0.8
2. 0.9
3. 1.0187
4. 1.5

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107. When a lead-acid battery is in fully charged condition, the colour of its positive plate is

1. dark grey
2. brown
3. dark brown
4. none of above

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108. When the lead-acid cell is fully charged, the electrolyte assumes _________ appearance

1. dull
2. reddish
3. bright
4. milky

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109. When the load resistance equals the generator resistance which of the following will be maximum ?

1. Current
2. Efficiency of the circuit
3. Power in the load resistance
4. Voltage across the load resistance

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110. When the specific gravity of the electrolyte of a lead-acid cell is reduced to 1.1 to 1.15 the cell is in

1. charged state
2. discharged state
3. both (a) and (b)
4. active state

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