Hello,
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Yes, you can peruse B.Tech after completing your 10+2.In fact, B.tech is done only after completing 10+2.
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B.Tech is a a undergraduate course which is down after completing 10+2. It's like a degree course without different stream
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Check out the Eligiblity criteria,

• Candidate should be 10+2 passed
• candidate must have physics, mathematics, chemistry and English as a mandatory subject
• Must have atleast 50% in intermediate