Would be something like below. The code compiles, but I have not tested.
If someone updated the salary in T1, did you want the salary and bonus to be updated in T2 as well? This does not do that.
Also, since you have salary in T1, you probably don't need salary column in T2 (unless you want to call it OriginalSalary and keep it as a record of what the original salary was)
CREATE TABLE dbo.T1(empNo INT, ename VARCHAR(255),salary DECIMAL(19,2), deptno VARCHAR(32))
CREATE TABLE dbo.T2(empNo INT, salary DECIMAL(19,2), bonus DECIMAL(19,2))
CREATE TRIGGER dbo.CopyIntoT2 ON dbo.T1
INSERT INTO dbo.T2
SELECT empNo, salary, 0.1*salary