What is balance of trade? 
or
Which two transactions determine BOT?
or
What is the difference between the values of exports and imports of goods called? 
or
When will BOT show a surplus? 
or
When is there deficit in BOT?
or
What is balance of visible items in BOP accounts called?

Balance of Trade. It is the difference between the money value of exports and imports of material goods (called visible items) during a year. Clearly, the two transactions which determine BOT are exports of goods and import of goods (visible items). Examples of visible items are clothes, shoes, machines etc. The difference between the values of exports and imports of goods is called balance of trade or trade balance. Exports are considered as income and imports as an expenditure. It includes exchange of only visible items and does not consider exchange of services (i.e., invisible trade). Alternatively, balance of visible items is called balance of trade.
Surplus or deficit BOT. Balance of trade may be in surplus or in deficit or in equilibrium. If value of exports of visible items is more than the value of imports of visible items, balance of trade shows a surplus. Then BOT is also called positive or favourable. In case value of exports is less than the value of imports, the balance of trade is said to be negative or adverse or unfavourable, Thus, the balance of trade is called in deficit. In case value of exports equals its imports, the balance of trade is said to be balanced or in equilibrium. Remember when balance of trade is in deficit, it is offset with the help of capital account.